There was lots of new mechanical stuff back then. I remember the first dice pool system in the Ghostbusters RPG. The very idea blew me away!
Some of that may be contextual. I'd seen the D&D variant of replacing the d20 with 3d6 (a small dice pool) well before I saw a game use it inherently. And I'd seen multiple dice (added together) used in Tunnels and Trolls in the 1970s before I ever played D&D. So, it didn't seem such a big deal to me.
When Call of Cthulhu first came out - my first experience of gritty horror gaming. Toon. FASA Trek.
These are all differentiation by genre. I already granted that happened.
The introduction of life path systems with Traveller
Was in the 1970s, and so can't be attributed to the 80s. And, while a few people like them, I note that few games today use such - probably for good reason.
And all that stuff TSR did.
Much of which were actually rehashes of D&D's core mechanics. I'll grant them the Marvel Superheroes game as innovative.
And then White Wolf comes along, and does all that stuff.
In the 1990s, and so not attributable to the 80s. And Shadowrun only came in late 1989, so wasn't around for the vast majority of the decade - it effectively was a 90s game, too.
I feel the 80s were a hive of industry and innovation.
In many ways, yes. New things were created. There were lots of game materials. But there was a whole lot of similarity in overall structure and design.
Consider - now we have games with all those 80s design elements *PLUS* all the design elements and playstyle support that has been developed in the thirty years since! It is hardly credible that today could be *less* diverse than the early decades of gaming, for that reason.
Though there were more boxed sets, which is a good thing.
Not a fan of boxed sets, myself. The boxes always got crushed, and the bits inside got lost or damaged as a result. I can't say I'm surprised or unhappy that they've waned in popularity.