I think the characters are a real plus and one of the only things that differentiate the Disney hotels from the cheaper off-site ones.
I agree in part.
What people often forget is that yes, Disney on-site hotels are very expensive but if you don't have an annual passport, you have to start calculating prices separately.
Tickets are very expensive, if you would want to go for several days, it might actually be cheaper to stay on site, where tickets and breakfast (and EMH) are included, than to stay offsite and pay everything separately (and don't benefit of EMH).
Of course, if you have an AP, then staying off-site is always cheaper
And you still have the EMH benefit (with a Dream AP at least, I don't know about the other two).