Kespa's entry might also mean the death of the foreign scene, or at least its eventual irrelevance. Here's why.
To understand my argument, you must understand the culture of Kespa and the way it functioned in the Brood War days. Back before SC2 came out, Kespa maintained two policies that allowed it to keep complete control of the BW scene: high barriers of entry onto SC:BW proteams, and anti-competitive practices that smashed any kind of outside challenge to its sanctioned leagues and events.
To join a proteam in Korea, a prospective player had to fulfill two extremely difficult tasks. First, the player would have to win a "Courage" tournament in order to obtain a semi-pro license, a grueling affair that even players such as Flash and Jaedong couldn't overcome on their first try. Then a newly minted semi-pro would have to catch the eye of a proteam and be added onto the team individually, or drafted in yearly events. There were exceptions to this restrictive system (such as IdrA, who was granted a pro license by his team, eSTRO), but for the most part, anyone who wanted to compete in the Brood War scene needed to spend a significant time in Korea.
Regarding anti-competitive practices: GOM TV started a SC:BW league in 2008. It was casted in English by Tasteless and various co-casters (lilsusie, Daniel Lee). It featured Korean progamers; the finals of the first season was Flash vs Jaedong. But slowly and steadily, Kespa pressured the teams to pull their players from the league. By the third season, only eight out of the twelve proteams were participating in the league. There was no fourth season. Kespa had control over both the bulk of the talent and the bulk of the sponsorship money; there was no overcoming that. So ended the experiment of English coverage of Korean BW.
a snippet of Tasteless's commentating
You all know what happened at the launch of SC2 between Blizzard and Kespa. Kespa was not seriously interested in negotiating with either Blizzard or GOM to secure rights to BW or SC2. They preferred to allow the issue to proceed to court. No deal was reached, and neither Blizzard nor GOM ended up pursuing legal action. If I remember correctly, the MSL and OSL reached individual deals with Blizzard.
The danger to the international SC2 scene is this: if Kespa-approved leagues destroy GOM with superior production quality and superior talent (and there is no reason to assume that this will not happen), the dichotomy between the Korean and Foreign scenes may regress to what it was in BW.
Currently, foreigners enjoy a wide variety of benefits regarding SC2 that they did not enjoy in BW. The most prominent SC2 tournament in Korea has a dedicated foreigner stream with English casting. Top-level foreigners can fly to Korea and, in many cases, have a Code A spot waiting for them. Indeed, this exact situation will take place when IdrA and DeMusliM take up residence in Korea. There are no restrictions on proteams from adding a foreign player to their ranks, permanently or temporarily.
If GOM dies due to all of the talent and sponsorship money being on Kespa's side, all of those benefits for foreigners will disappear. If Kespa does things the way they used to, it will be impossible, for example, for an EG player to participate in Korean SC2. It is also unlikely that OGN or MBC (if MBC still exists by then, which is doubtful) will provide an English stream.
In that case, SC2 will be split into two scenes, foreign and Korean, with the bulk of the talent in one tiny country. It'll be Brood War all over again.
This prophecy of doom relies on two things: one, that Kespa is utterly inflexible in its dealings with GOM and Blizzard; and two, that Kespa keeps the high barriers of entry into its tournaments that it has had in the past.
The entry of the Kespa-sanctioned teams into SC2 cannot be interpreted as anything but a very good thing for spectators of SC2. Within a year, players like Flash, Jaedong, and Bisu will bring the sport of Starcraft 2 to new heights. This isn't a possibility. It is a sure thing.
However, the future might hold very bad things indeed for foreigners. With Kespa's history of stubbornness and unilateralism, there's no reason to think that things will turn out for the best. The fact that Blizzard invited 4 BW pros to Blizzcon might be a sign of the ice thawing between Blizz and Kespa. But until an official announcement to that effect is made, I won't feel optimistic about the Korean situation in the least.