The introduction of Denny again is making me think, very seriously, that this is the beginning of writing Izzy out. We all know she wasn't happy with her character over the last couple of series, with all the Emmy fuss etc, and her 'not really having any good storylines'.
I forsee this storyline for her.
Izzy begins a descent into madness. Cue plenty of opportunities for acting - drama, tears, happiness etc. She's seeing - no, she's actually touching someone who doesn't exist. Either they're getting ready to drop her by writing her out in some way - will she die? Will she go off on a quest somewhere to get in touch with other realities? Will she kill herself? Hey - we haven't had a resident suicide, have we - or did I miss that episode?
And we can have Alex trying to save her, fighting with an impossibly perfect ghost to try to pull her back, before finding her dead or dying, still smiling...
Yes, methinks Ms Heigl has p1@@ed off someone she shouldn't have, and is on her way out.