Regarding this whole, "It's Walt's fault" from Mike's speech thing...
Put it like this, Gus had been planning on replacing Walt. Now we don't know how he was going to do it initially, but here are some things to remember about that situation. After Tuco died. The cartel wanted Walt's ass dead... period. Gus also knew that Walt had cancer, AND he knew that his damn brother in law as a DEA agent.
Gus had Gale working for him... with all the shyt he knew about Walt factored in, he knew that he would have to replace him eventually. Gus was prepping Gale as his replacement, and the cartel wanted Gus to give up Walt. And Gus was telling them that he would handle the situation.
So yal implying that shyt was just peaches and that Walt fukked everything up with the operation need to remember all that shyt that was going on. It seamed like Walt was all good before he killed Gus' two dealers for Jesse, but best believe Gus was preparing to run his shyt without Walt.
Mike's speech was his side of how things went. Walt was protecting Jesse when he did that shyt. When he murked the dealers, that's when Gus said, this dude is unpredictable and just escalated the process of him being replaced.