Arcturus with the device...bit corny.
Kerrigan killing Arcturus...satisfying. It was what I'd predicted for quite awhile.
Leave humanity to its fate...um, what? I mean, obviously we're missing a lot here, but if it means what I think it does, with the Dark Voice...well, she may not be the Queen Bitch of the Universe, but she's still a bitch.
The zerg leaving, which I suspect might be influenced by BGS and the centurions (think Metzen is a fan) isn't an issue. I kind of like it, the idea of the zerg going free...yes, they've brought death, but only because of directives (e.g. the Overmind) or the lingering effects of said directives (aftermath of Tassadar's sacrifice). It also prevents a team-up for LotV seemingly, which is good IMO.