I can understand taking this route. It requires a lot of faith from me though.... so I dislike it. I've still tried it, but I don't really want to make huge choices on that basis when it comes down to it. I wish I was given a small sign at least. I mean, I see better collective examples of Batarians than I do Krogan. It's believable to me that the Batarians might reform their society with the Hegemony gone --- because I see what they're like in the games. They're very human, more or less. With Krogan, I'm given nothing to base this kind of grand vision of the future on. It's just faith.
I don't know that it's faith so much as desperation and some willingness to give them a chance. I tend to agree with Victus wrt the need for krogan allies in the reaper war. He also says "I'd rather have a grateful ally than a bitter rival" or something along those lines.
We talk to only one krogan female, but I expect the others have similar feelings. She is their shaman and apparently a leader in the female clan. She's very aware that the krogan brought a lot of it on themselves, and seems quite eager to avoid a repeat.
edit: Well, there are the epilogue slides, I guess. I still have plenty of questions though. The epilogues make the Cure look peachy no matter what you do... but in my mind, it plays out like a delicate house of cards, where you need everything in just the right place..
The slides kind of ruin the complexity and fun of it. It's easily the "right" choice.
The slides do show them rebuilding, but don't tell us much about their relationships with other species. If you really think about how they've been living with the genophage, and how much the fabric of their culture will change without it - well, it could be the impetus for some significant changes. Remember the ambient conversations in ME2, where some Urdnot men were talking about visiting the female camp, and one of them was wondering whether some youngster was his? Things are going to be very different for them when they can have their own mates again, assured of paternity.
All that said, the cure might not be permanent. While those females were in custody, the salarians likely got a lot more current genetic information about them. It's something the salarians monitored, anyway - krogan were adapting, and Mordin's team needed to modify it. Looks to me like Tuchanka might need the salarians to build them a new shroud since it was getting wrecked. I expect the rest of the galaxy will be keeping tabs on the krogan, the salarians standing by with another round of biowarfare if it is needed.