I'm playing around with the new PHB, and it is interesting to me that with the new lucky feat, I can get Miss Imogen carried over to the new rules for the most part. There's very little that comes from her Samurai subclass, so she could slide into a different subclass and be PHB only. She has the (mostly plot-derived) one-level dip in Sorcerer, which could be kept, but since subclasses now come at level 3, she'd need to use Mage Armor instead (or take the dip in Warlock instead, which would let her have Mage Armor all the time through an invocation, but not have a cold-based cantrip. Anyways, it's a fun experiment.
I'm not saying that switching over is what we're doing, or what we should do -- for me it was just an experiment in what the new rules allowed and what would result.