Each thing will be pretty short, to be expanded if it's desired.

[hider=Game of Thrones]
You saw that one coming, didn't ya.

I'm going to contradict the first reply and say that the revisions would be well suited starting at Season 7 in general, optimally retuning that starts at Season 5 and works with Season 6, but especially change up the framework at 7. It's not that I necessarily had something against the path, rather, the season being short. This was the first step to downfall, the lack of time put into the details, the handwaved movements from one region to another. Halt the season, spread it out, use the gummy goodness types of storytelling to fill in that made the first four seasons sell in the first place, continue up to the point of S8E3.

S8E3 I would remove entirely in favor of stretching it and all subsequent events over two more seasons, with the revised show ending in Season 10, taking advantage of the liberally given resources to the directors to flesh out character arcs and plot points on a fairly individual basis - giving each character something of a wrapup, even if it isn't the end of them. "The Long Night" features the greatest macguffin known to Westeros, and it was halted in a single siege on the first real battle below the wall. No. They need impact, and I would make it further down the path.

The sequences of 4-6 are their own nightmare of terrible pacing and design, and I can get into those specifically if desired. Otherwise I would neuter that entire stream of events, possibly taking a few of them and rewriting them to have a bit more plot cohesion into a much wider picture. I haven't put much thought in what an S7/8/9/10 would look like, so on elaboration I'd only be able to speak in abstracts. I'm not paid for such a revision, so I don't feel obliged to go all the way. What I do know is if I was in that position, I'd stretch out events, put a bit more focus on individual stories, perhaps explore some war weariness, and in creating outlines, attempt to construct the story by reasonable character decisions based on precedence, not by a desire to simply reach the ending. Character driven first, then see where the ending can be worked in, much to be figured out in abstract before even moving on with the seasons. At the starting point of S7, 8 should be roughly figured out and 9 in abstract, with 10 being on the radar to avoid the curse of endlessness that completely operating character first would inflict.
[/hider]
[hider=Starcraft 2]
SC2 was very... bright, and the impact, not well supported. WoL would be reviewed and redone for better alternating branches in player decision making and less 'dur' in the portrayal of Mengsk and his media. I believe it was said that Raynor was planned to have more conflict, a drinking problem, so on that would introduce real struggle to the protagonist, something that was deliberately taken out for being too dark or something. Fuck that, did they not create SC1 and Brood War? There was a formula there that I would continue.

HotS at the very least would have adjustments to make Kerrigan appear less strictly bipolar and more legitimately conflicted, with better progression into her zerg-like attributes and perhaps an effort to have the player somewhat decide if the descent is a struggle or something she feeds at a greater cost of her humanity, with advantages and disadvantages coming from either approach. This would be complicated to implement, of course.

LOTV did an okay job, but built on roots per above that would mean a lot of its tone and details would be shifted accordingly. Among other things I've never been impressed with the Hybrid. Simply, they lack impact, and I would intend to make them straight up more threatening. Two classes - the weaker ones that are minor blends, and serious monstrosities that would individually be incredible threats... worthy of dueling a player-managed Kerrigan per the last campaign. There's a lot of potential that was unfortunately missed.

The epilogue was straight up botched, and I think the above gives some insight in how I'd approach it, though I could elaborate if desired. This is one field I have thought of extensively.
[/hider]
[hider=Diablo 3]
Well, this one I can put simply. More competent antagonists that don't tell you all their plans and reduce the raw boundless power of the protagonist. A shameful display from a series containing D1 and even D2's tone as the standard till then. D4 seems to be taking a look back in that direction.
[/hider]