The warhound is an attack move unit. What I mean by this is that you do not need any fancy micro (nor is any possible) to make the warhound effective. You attack move into your opponent and you're set. Target firing and pulling back hurt warhounds is literally the ONLY form of micro you can possibly do to increase their effectiveness, and this can be said to be true for literally any possible ranged unit design (even marines). Why is this bad? Well to understand it in the first place let's look at why this is good, and the design philosophy Blizzard seems to be approaching the game with.
There are two main conflicting philosophies for game design in this context that apply to starcraft. The first is that you design a game that will be fun to watch and will inspire people to play. This philosophy relies on esports viewership enjoying watching the game and wanting to emulate what they see in pro matches on their own. For example, in Brood War you might watch a TSL match with JF, see him absolutely demolishing people with reavers, and get inspired to go try out some shuttle/reaver micro yourself. Since reaver/shuttle micro is difficult, you may fail at first. With a little practice, however, you too can enjoy the fun. The second design philosophy (which seems to be what Blizzard is employing) is to create a game that everyone can easily grasp and understand, and thus you attract new players because they are not discouraged by the game being difficult. With this approach, viewers can watch pros demolishing everything with colossi, and then even if they are in bronze league, they too can enjoy the fun of seeing giant laser beams obliterate everything. (Here's the secret: no one thinks colossi are fun to play with after the first couple times)
The inherent problem here is the idea of replayability. When a game is too easy, it is fun the first couple times and then completely loses its charm and gets boring. I love Portal to death, but once you understand the puzzles and what you are supposed to do, it is so easy upon playing a second time through that it is just not fun or worth the time anymore. In order for video games to continue being played for years instead of taking the route of pretty much every single EA title, they need to have some inherent difficulty that is not knowledge based (because anything that's only difficult because you don't know what to do will no longer be difficult once you understand the solution). This is where execution and tactics in Starcraft come in. If the game was only strategy and no tactics, it would get boring extremely quickly and there is no way it would be an esport. It's the simple difficulty of executing a tricky task that makes playing starcraft so fun no matter how many times you have already played it. The problem with Blizzard's design philosophy is that it overestimates the pros of low-difficulty, and underestimates the pros of high-difficulty.
Low difficulty mechanics
Pros: Newbies get less frustrated because there are less things to mess up.
Cons: These same newbies get bored quickly because there is nothing exciting to do (as all the excitement died after the first couple times executing something so easy). Esports is delegitimized and experiences more variance due to a lower skill cap and less opportunities for pros to excel. Pro matches are not fun to watch because any bronze newbie could execute what they see just as well as the pros (obviously this is an extreme example taken to hyperbole). The game does not last nearly as long in popularity because there are no inherently rewarding things to do.
High difficulty mechanics
Pros: Newbies get inspired to actually spend time playing the game because they see professional players doing amazing moves that they didn't even know/think were possible. It encourages them to continue playing the game because they still have many things they haven't mastered. Players actually enjoy the game because there is an inherent enjoyment in having practiced something difficult and executing it correctly. Pro matches are more fun to watch and esports flourishes because people LOVE watching other people do things they can't do (don't believe me? Just look at the olympics... pro sports... BROOD WAR). The game's shelf life is extended tremendously due to the increased enjoyment in replayability.
Cons: Newbies get more frustrated because they cannot perform tactics they see professionals use upon first try and must actually spend some modicum of time practicing.
So now that I've explained why having difficult mechanics is important, let's look at the warhound. There is absolutely nothing difficult about this unit. It is fast (meaning you don't have to already 'be in the right place at the right time,' instead you can react quickly to your opponent when you are caught off guard), and you do not need to babysit it in the slightest. You attack move and then either go back to macro or sit there staring and watching, bored out of your mind because there is so little micro to do as mech in midgame (until you get ravens or are using siege tanks, and why would anyone build a tank while the warhound exists). Pro matches will never be inspiring to anyone, because they know they could execute exactly what the pro is doing just as well (not hard to attack move).
This is why I do not believe the warhound should be balanced. No amount of tweaking values to make it statistically balanced will make it a good unit for the health of starcraft both as a casual, fun game, and as an esport. The Warhound needs to be overhauled, or completely redesigned. When creating new units, I would emplore Blizzard to look at the design philosophies that made Brood War so unbelievably popular and long-lasting. Many units were considered extremely overpowered in certain ways (dark swarm, anyone?), but in order to make this work, they would sacrifice strength in another way.
Let's look at the Reaver. I use the Reaver as my example because I believe it to be the most exciting (for both players and spectators) and best designed unit in the history of Starcraft. Nothing got spectators more riled up than the nervous anticipation of seeing scarabs running towards their target, not knowing if they would hit or not or how much damage would be done. At the same time, they took an immense amount of skill to use properly. Since their AoE attack was clearly ridiculously overpowered, it was balanced out not by reducing the damage or some other boring stat change to make every unit equally powerful (which almost seems to be Blizzard's intention with SC2), but instead by making it hopelessly immobile and by making the ammunition cost resources and take time to build. Thus the difficulty of the reaver is as follows: You need to get a reaver(s), get a shuttle for mobility, and constantly rebuild ammo. Then when you engage you have to babysit your shuttle (because it's a huge investment to lose in the blink of an eye to 2 scourge for example), drop the reavers, target fire (probably more important than target firing for any other unit in the game due to the pathing, splash damage, and possibility of duds), and then pick them back up in the shuttle to mitigate damage while they wait to be able to shoot again. On paper this sounds incredibly complicated, and you can be assured a newbie would not pick up starcraft and go for a 2 reaver shuttle drop in his first day, but in actuality it looks beautiful in pro matches and is not so difficult to emulate at a low level. You might not have the game sense of JF to go exactly where you need to, and you might not have the perfect shuttle control to constantly move it around and pick up the reavers without decelerating, and you might not have the perfect target firing to pick off the most optimal targets. But hey, you are still going to be able to execute a reaver drop with a reasonable level of enjoyment no matter what level of player you are.
This is the example and ideal I feel Blizzard should be using with every unit they design. Make a unit that is difficult to use perfectly, so that it's fun to use every time and will inspire viewers. If you make an easy-to-use unit like the Warhound, you might not discourage newbies at first but you certainly won't encourage them to continue playing, as the unit isn't actually fun to use.
You may enjoy color-by-numbers as a 3-year-old because it's not overwhelming and you get some guidance. Once you reach any reasonable age, however, these types of "easy-mode" activities hold no enjoyment. Adults generally prefer activities with some reasonable level of inherent masterable difficulty.
So why is this game being designed for children when it is rated T for Teen?
Even if you do not agree with me about high skill mechanics being necessary and even vital to the success of Starcraft 2 as an esport, what is the justification for putting in a unit that fills exactly the same role as the marauder? Terran already has an attack move, hyper mobile, tanky, high dps unit that can only attack ground. Why do they need a second one?