the "Street Rod" franchise was pretty awesome as well
someone made "Street Rod 3", so I guess that's as good as it gets?
http://www.streetrod3.com/apart from that, I'd love (read l.o.v.e) to see a continuation of Epyx "the Games" series
(i.e. Summer Games/Winter Games/California Games/World Games)
afaik there's 2 Summer Games + The Games - Summer Edition,
same goes for Winter Games
California Games has 1+2
and poor World Games only has 1 =/
also Track & Field series needs to be continued
Spy vs. Spy (yes, I do have the "new" version for Xbox1... *shudders*)
first: Spy vs. Spy
then: Spy vs. Spy 2 - Island Capers
then: Spy vs. Spy 3 - Arctic Antics
and (according to the ending of Spy vs. Spy 3) there "would" have been:
Spy vs. Spy 4 - Spies in Space
I'd love to see follow-ups of both International Karate series (1, 2 and +)
and Exploding Fist series (again; 1, 2 and +)
what made the "+" spin-offs so great was that there were 3 players on-screen at once
(that and the fact that those are the only fighting games I play =)
and then of course Barbarian 1 and 2 (Palace) - I've tried the remake and the Xbox1 "spin-off", but they kinda sucked
Shadow of the Beast series actually got rather interesting with the third installation; perhaps continuing on those as well?
The Bard's Tale series 1-3 (and Dragon Wars, which I'd call nr. 4) (yes I have the "The Bard's Tale for Xbox1 as well, but... has really nothing to do with the originals)
Eye of the Beholder/Lands of Lore series (Lands of Lore 2-3 wasn't really that great, but with new engines, etc. who knows what could be done?)
Ultima! (in the vein of 3-5 IMHO), although I love(d) VI and VII (and partly VIII), IX sucked pretty badly and I've never gotten into Ultima On-line (just no more spin-offs like Martian Dreams and Savage Empire)
perhaps Ultima Underworld 3? (I love Arx Fatalis, but it's *not* Ultima ^^)
sorry.. I've got heaps and heaps of games I'd like to see continued ^^