He'll change the messaging/branding of twitter, w/o actually changing anything about it - he's got too much money invested to run it into the ground. Even he knows that social media platforms are fragile things, where the successful ones have captured lightning in a bottle w/o really understanding the why. (Mostly it's called "luck" - there are graveyards filled with failed platforms)

Wouldn't take much to upset the delicate balance over at Twitter that registers as "success" - at best, he maintains the status quo