You can teach someone on anything. The time involved and techniques will only vary slightly.

I am much more confident with an instructor saying, "I'm going to teach someone on a warbird", than a newbie saying, "I want to learn on a warbird".

There's a big difference between the two.

PS Personally, I like to train on an intermediate flier like a 4*. But you have to be willing to dedicate yourself to the trainee.