Thompson won't be the player he was, at least not initially, I guarantee it. I bet he will still be able to shoot, especially if left open, but I don't think he will be the defender. the hard cutting off ball player he once was. He might get there down the road but he has been out for 2 years now, the pace of the NBA isn't something that can be replicated in practice.
Klay's return won't be a problem for the Warriors; assuming they ease Klay into the rotation. Wiseman on the other hand... I think he will be a real issue, they were FAR better without him last year. If they force themselves to play Wiseman in order to develop him (probably good idea long term, probably disaster in the short term) I think they struggle in the minutes he plays. He is one of many players who relied on athleticism over skills to dominate at lower levels. He was already struggling to adjust a year ago and now he is coming off a serious injury and on a team with astronomical expectations.