I am going to jump the gun here as I know all about how this forum works as I have owned one since 2001
The Admin has the ability to add as many themes as they like, and they can set it so anyone can use use any theme, but they can also set it so that a default theme is applied and the user can change it if they please.
There is no harm in trying one out, something like a light blue that is as easy on the eyes as this one.
If it doesn't work it doesn't work but there is no harm in trial and error, you never know some people might like a new theme, some people might not, but once they see the new theme I know from experience people can easy change there minds.
Anyways this is a admins decision, but at least think about it