I don't feel bad for Louis at all, he went with Hardman to start and opened up a major wound between himself and Jessica/Harvey. I know in the end he ended up on their side again but its hard to expect them to just forgive him then and there for being in the mess in the first place. Things will eventually get back to normal but to expect it to return to normal just right away is unrealistic in my opinion.
As for Mike he is an idiot for sleeping with Tess but its not like a relationship was going to happen with him and Rachel anyway. The problem was still there, Mike would have to lie to her and even though he doesn't really have anyone else in his life I don't think he'd be able to do that. He already had an opportunity and he failed, why would it suddenly be different a couple of months (I'm assuming that's the timeline) later?
Overall very good season finale, can't wait til it starts up again in the winter.
I liked that Mike bluffed to the other partners to save Harvey and Jessica. He thought quickly on his feet and realized that many of the partners didn't trust Hardman and would be pissed that he forced them to give away some of their money to cover for himself.
Louis is in a tough spot. He went with Hardman at first because everyone else at the firm took him for granted. He desperately wanted someone above him to recognize all of the value that he brings to the company and he thought Hardman was that person. In the end, he realized that he was wrong about Hardman and now he is forced to crawl back to Jessica.