I don't know about options to use regular joysticks on the CDTV. That would be the only other thing I might be interested in doing to it, or I may just leave it like it is now and enjoy it for what it is.
Here's a picture of one of those joystick adapters for the CDTV.
LinkI got this one fairly cheap, but unfortunately it only works for one joystick. The second interface doesn't react that well. IIRC joystick left and right movements are not registered. Sucks, because I really like playing old school two-player games when I have friends over and the CDTV is perfect as a living room Amiga.
There was a similiar interface up on eBay recently but it went for an absurd price. 50 euros or more I think.
But you're right. The CDTV, despite its failure and quirkiness (or perhaps because of it), is a wonderful piece of Amiga history!
:-)