Considering how the 80’s went, it’s pretty easy to imagine that mecha could have remained a genre that continued to evolve gradually, but would never be completely revolutionized again. Then again, it’s also possible the genre would have declined into a small isolated niche. But I’m getting ahead of myself, and in fact 1994 was a good enough year for mecha that I think it was clearly already rebounding. G Gundam is one of my personal favorites, but didn’t really “change anime” as much as most of what I’ve been mentioning.
Depending on how you look at it, I think it took until Magic Knight Rayearth in 1994 (the manga started in 93, but the Mashin/Rune-Gods didn’t appear early) before there was a great example of a series that had mecha where mecha were nowhere near the core concept.