1) Attacking the press. This one is arguable because he seems to be getting some benefit from it, but I recall reading early on that this would cause issues for his administration--and it absolutely has. Outside of reporting simply influencing things like his approval rating, it has resulted in actual resignations and terminations of people working at the white house. Not to mention a crackdown on security clearances. The press' obsession with him (which is largely of his own making) is hampering his ability to do his job and nominate/hire the people that he wants.
2) The Comey firing. Regardless of whether or not people want to argue that it was warranted, the how of it resulted in Mueller being appointed and all this other hooplah. It's pretty tough to say it wasn't a mistake when you consider how flustered the man himself is over the whole thing. The scrutiny it's brought has led into multiple legal complications for him.
3) Same as yours. Even if the Republicans had just managed to repeal the ACA, I think they'd at least look like they had a plan for governance. At this point, there's going to be a lingering image that all they know how to do is get in the way for some time.
4) His combative nature within the party that got him elected. If he seems reckless and frustrated now (although he's been a little more confident lately), it's only going to get worse if the Democrats take the house. I think that right now Republicans have played along because working with him has still had the benefit of being able to push some policy. Once that is gone, I think things might begin to get nasty as tempers flare and his relationship with Republicans frays further. While it seems like his party at the moment, I'm not convinced that's sustainable. Consider the turnover at the white house. The man doesn't seem good at maintaining working relationships.
5) Two scoops of ice cream.