Two years of e-sports as we know it, less the Warchests. Map becoming more varied and complex. Co-op and campaign users slowly decreasing. Then the community evolving to a model close to BW’s one, with less tournaments, but auto-funded, with the different e-sport streamers possibly federating to managed those.
And after an undefined interval, a new game.
SC3 will be an RTS, the only question are how many new features it will have compared to SC2 (hero units in particular).
The SC universe could delve into other genres, the canceled SC Ghost and Heroes of the Storm are an example ; but considering how many franchises Blizzard/Activision already has, and how unlikely they are to bet on entirely new concepts, it’s probable they will continue the current genres being carried by their respectives series (WoW for MMORPG, OW for FPS, SC for RTS etc.) .
As for what’s next, well Diablo IV ; then the question will be if they go for an experimental Warcraft IV for the RTS genre, or start SC3’s development. 