I liked the stuff with Wes (and you could still do that no matter the character's role), but I agree with the other points. Yeah I don't see why she couldn't have been CEO from the start. You could still have had the rivary with Lindsay too.
In fact I don’t even know if there is a reason about why in season 5 we have Eve instead of Lilah. I completely don’t understand the writers ! What did they think ? I mean from a scenario point of view, Lilah as a ghost could be the relation between Angel and the senior partner. It’s really stupid to not have taken the opportunity. Did the actress want to continue in the series ? I try to find a reasonable reason which would explain why they didn’t keep Lilah.