I never have problems coming up with scenarios, I think folks that rp with me will confirm that, but on games I have alts on its not unheard of me to offer either alt based on player pref since I don’t know which one of theirs they might be wanting to either rp because its easier or they are trying to get more time on them and don’t have as much opportunity or that some people’s pcs just are more limited than mine so they’d prefer one over the other.
As someone who is rarely proactively asked to RP and has to do a lot of the asking/arranging if I want to RP it sucks to worry that people are going to judge me for that or they won’t give me a chance because I offered to be flexible but otoh I don’t really have a choice but to brush it off and keep asking if I want to be able to RP.
As an asker there are plenty of people who accept and then don’t know what they want too. Oh anything is good/no not that my pc wouldn’t go there. Its a fine line to dance as an asker because I’m sure those folks get judgy if you don’t come up with the right guess too. When two players agree to rp im not sure I think either one owes the other a greater set up responsibility esp if there wasn’t a specific scene invite. It’s good to touch base to make sure its something that works for both which can be hard for randos so you may have to ask would you prefer the vampire alt or the werelobster?
If I have a strong pref for something specific I solicit that on chan (I’m going to set a scene in X, would anyone like to join me?) But absent that i like to see who I get, look at any aspirations and then might ask them if they have any prefs. I dont think everyone does that but I don’t see it being really abnormal either.