Killer Instinct. The older games have not aged well at all compared to the reboot. Even when it was new they were niche. The first games were more known for the unique he characters then fighting mechanic depth.
I find this with a lot of fighters, as technology has improved so have the gameplay as it's become smoother and the gameplays are more streamlined because the characters are no longer 5 pixels or 10 polygons :P MK and SF both went through a lull during 6th gen and came back stronger in 7th and 8th.