The reason I enjoy playing Terran is because generally when you look at their units and capabilities, virtually every single one exists in some primitive form today. We have guns, tanks, planes that can hover, flamethrowers, grenade launchers, EMPs, etc. etc. Because of this, when I try to think of new Terran units my instinct is to look at actual military gear and see if anything is not being well represented in this game, and if it could have a place. After a bit of soul searching, I think I've come up with an interesting re-work of the Medivac which would help some problems Terran has been having, and also result in some interesting new micro mechanics.
It's so simple. Why don't Medivacs have guns on them? Given their role it seems like a very obvious thing to have.
How It Would Work
An empty medivac would have no attack. Their would be a gun on each side of the medivac which could only shoot in an almost complete semicircle in their side of the medivac (no shooting straight ahead/behind). DPS is something which would have to be balanced, but I envision it being similar to viking fire. Medivacs would have a ``Load Gunner`` ability for each side and would have to have at least the number of marines (anything else too bulky) as the number of gunners they wanted activated. Those gunners get locked into their slots, and need to be unloaded from their slots before getting dropped from the Medivac with the other units. Medivacs are still limited to 8 slots (i.e. a medivac with both gunners loaded could still only carry 3 mauraders.)
Why It isn't Necessarily a Buff
This rework is both a buff&neft depending on the situation. In a large pitched battle chances are you'd want your units on the ground. This is because once a Medivac shoots, it becomes an attacking unit. Therefore it will aggro enemy AI to fire on them as opposed to your units whom they are healing. You don't want your medivacs getting shot, you want your units whom your medivacs are healing to get shot. It's not really a nerf, but just wanting to point out that it's not an ability which I think will be left on at all times regardless of situation.
Situations Where it Would Help
People have been complaining a lot about fungal lately for a variety of reasons. One of the main ones is that lategame Z is unbeatable. Of course we all really know that this isn't exactly true, and as Terrans what we need to do is not engage head on, but abuse mobility to attack opponents bases. The problem now is that it's too easy for a single infestor to shut down multiple medivacs with a fungal and a couple IT. If Medivacs can shoot back enough to kill an IT or two, suddenly Zerg needs like 2 or 3 infestors. Not a huge deal, but can make a big difference in these kinds of situations. My philosophy is that each race should have different strengths at different times (otherwise we'd just be playing Age of Empires), so if the Zerg phase of the game is too strong, lets buff Terran's strengths instead.
Why it would be fun
Besides the fact that miniguns are awesome, this change would support some pretty interesting micro. Because the attack functions so differently, medivac micro would be very unique. You need to make sure you have gunners loaded properly, and need to arrange medivacs to make sure that one or both of the gunners can be firing at the same time. Because the medivac is able to move while attacking, this could lead to really cool focus firing abilities and harass options.