Heidenreich wrote...
WHY CANT THEY DO THIS FOR HAWKE, WTF.
Because Fenris' relationship with Hawke is different than the one with Isabela. Consider how different Act III Fenris is from Act II. Isabela has shown interest in him since Act I but never put any effort into acting on that interest by the time the third act comes around Fenris is finally in a position where he's ready to 'test the waters' so to speak with Isabela.
With Hawke, the love scene in Act II and the regret Fenris feels for leaving that night is the key focus. By act three Fenris has come to terms with his past and is ready to move on with Hawke, who has been there for him despite what happened with them. Its continuing the relationship rather than starting one.
Also, Fenris' romance is a bloody awkward thing to bring up what with the whole walk out issue:
The Warden's Prison
Carver: She's still sitting there in the corner.
Varric: Yeah, and she's still got the thousand-yard stare. Good job Junior.
Carver: How was I to know what happened between them? I've been in the Anderfels for three years, all I heard was what Isabela told me.
Varric: It's a sore spot for the two of them. I've seen her take on oxmen, blood mages, and even a band of raiders but that whole deal with the elf is the only thing I've seen stop her dead in her tracks.
Carver: I should cheer her up.
Varric: What are you going to do, dance a little jig that will make everything better?
Carver: As a matter of fact that's exactly what I'm going to do.