Just wouldn't totally surprise me. They seem pretty ruthless in terms of knowing what people's ceiling is and improving. Roberts, Neil and Patterson haven't done anything wrong, but were seen as players with championship ceiling so they're straight out (or not used) with no sentiment. Speakman has been outstanding in his role and we've improved dramatically, but they obviously think for PL progression they need someone else so out he goes.
No reason to think they'll be any more sentimental about the head coach. Maybe they'll see the great work he's done and want him to continue (which most would support). Or maybe they saw him as the best man to get us up, gel the side together and set us up tactically to be hard to beat, which was seen as the best way to survive in this league. But the next step might not need the same, he might not be seen as having the proven ability to take that next step, and we'd now have a much wider pool of head coaches to choose from.
Not saying he should be under any pressure at all. For me he shouldn't. But if we look at how they've operated clinically, without sentiment, bordering on ruthless, it wouldn't be a huge shock.