Disclaimer: I worked for Disney for years...first in the feature animation division, and then disneyland.
Most of the character toys are crap. Movies, I have no objection to, but those are quite limited. When they kids ask for a specific movie, i have no problem with them watching it...but then again, they haven't watched tv in about 4 days simply because they havent asked for it....so i guess its the mood of the house that dictates something more so than any "rules"
Some character toys are ok...but few of them. For example, we have a 101 dalmatians "vet" set which the kids love to use on their animals when they are injured. then, there are toy story legos which they both love. the thing is, any character (whether its madeline or ariel, or a classic book) can be overdone. its just that most movie/nick characters are easily overdone.
So, how to tactfully say that you dont want this stuff? maybe limit character items to children's items that are naturally NOT open play? if they kids received disney slumber bags, would i object? no...simply because there is nothing limiting their imagination in something that they sleep in
i can easily say no character clothes, simply because school doesnt allow that.
but i also give them soooo many ideas of things to purchase (thanks to amazon's universal wish list, which lets me add any item from any website) that they "get" what I want for the kids. that being said, if they purchase mickey mouse garden tools instead of generic kids garden tools, i wont object.
again, because they are not limiting imaginative play.