The Piko cart, if nothing else, offers solid value, with its 20 games. Top Racer is excellent. Many of the platform games are great. Exploding Fist is an oddball, though — a really bizarre take on the original.
As for Ikari Warriors and Rastan, I’d probably hold off to see if they can get the arcade carts up and running next year. Right now, they’d be likely to go for NES ports, which would net you an OK Ikari Warriors. Rastan: I guess they could do the SMS version, which is pretty good, if not as good as the original. Whatever anyone does, avoid the Technōs cart, because it’s bloody awful unless you’re a BIG fan of NES brawlers.
(And, yeah, the C64 take on Ikari Warriors was pretty great, albeit very different from the arcade version.)