I played the D&D games heaps when i was younger, at least 2 of the arcades had a D&D game and they were great fun.
Just as Kajoq said there is more to them than the usual punch, kick, jump combo of your usual side scrollers.
Having said that, if you're just building a MAME cabinet without consoles I'd play one of the D&D games first to see if you like it enough to justify the extra buttons.