It could be argued that the reaper war throws that out the window, since waging war with the reapers doesn't leave a lot of room for his plans to continue. I don't know if I'd say that Mordin was rewritten. He already seemed conflicted in ME2. Deciding to reverse the genophage as a point on his bucket list didn't surprise me at all. The guy went off soul-searching to come to terms with what he was a part of.
It's still shows that Wrex is untrustworthy at worst and unreliable at best.
In Mass Effect 2 he promised Shepard a Krogan army at his/her back, and in Mass Effect 3 he's giving Shepard the cold shoulder going on about how he/she isn't a true friend unless the Genophage is cured. Really Wrex? All of that help I gave you on the Citadel in hunting down Fist, all the trouble I went through to track down your family armor, and all the sense I talked into you on Virmire doesn't count? Am I only a close friend when I do the things you want?
And what is Wrex's deal with playing the race card? The first thing he does when the Turians come to him for aid is to smart off about how poetic it is for them to come crawling to the Krogan for help, and when on Surkesh all he does is insult and threaten the Salarians working there; people that working with him to get Eve out. The narrative tries to portray the Krogan as the poor victims of a cruel, racist galaxy, but Wrex seems to be the only one who is holding on to past grudges and being a bigot; or does he not get that racism goes both ways?
Besides, curing the Genophage during the height of the Reaper invasion is horrible idea. Sure, it will provide a "moral boost" to the Krogan forces, but what happens when the Reapers start targeting pregnant woman and children? Fatalism is actually a better emotional state in an all out war for survival, because you don't need your troops dwelling on how things are doing back home when there's fighting in front of them.