Hmmm....I voted, "No." I didn't want MK/Stella to leave and would've preferred that all the cast stay together and have the show go out on top with stronger writing. That said, MK leaving does make it easier to distance myself from the show and accept the prospect of its ending.
I don't have a problem with MK's attitude towards Stella either. From the latest interview, it sounds like she wanted Stella to be written and portrayed in a more positive way and didn't feel like that was happening, so I can understand if her interest in portraying the character has diminshed.
Re: why she's not coming back to wrap up the character, maybe we'll find out more of what happened behind the scenes at some point. Was MK even asked to come back for one or two episodes, or did the producers think it was best to just move on quickly? And if MK was asked to participate in Stella's exit, did she decline becasue she didn't agree with what was planned? Inquiring minds want to know....
As to whether the show will survive much longer, there are a number of factors which probably will play into that outcome, including the timeslot change and how well they are able to transition in the new character. Considering NY's new timeslot, I would think one of the main things they need is a stable, loyal audience who will follow them to Friday and hang around as they "find themselves" again. Losing a lead character is not a trivial thing to overcome as other series have found out, and I'm still skeptical this will be a positive factor for NY, especially when it comes to the broader audience.