Mostly preaching to the crowd here, but here's some thoughts I posted in another thread on recent innovations in game design, logged for future use:

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GMless play has seen major advances. Sure, lots of folks were doing it before on their own, but now there are lots of games intentionally designed for it.

Parallel to the rise of GMless play has been a rise of player-facing structures and mechanics that involve players more directly in worldbuilding, campaign framing, and content creation, both before and after play begins. Again, a lot of this existed before but our available toolset has been dramatically strengthened and relies less on GM adjudication than it did before.

Single-session or short arc games (that finish in 2-4 sessions) have also seen major advances. Again, lots of people were doing this before, but most published games still previously assumed that a long-term campaign without a built-in ending was the norm. We have gotten better at endings!

Even in games with traditional GMs, we have gotten much better at explicitly calling out and explicating the duties of the GM (and players, really) and talking about how they change from game to game (or, more often, what this particular game requires of players), rather than assuming that all GMing is fundamentally the same or that the GM needs to read players' minds and deliver what they want rather than talking about the game's needs with them and getting them on the same page.

I would also argue that we have gotten smarter about writing shorter or more densely packed texts that directly inform the play experience at the table, rather than including pages upon pages of descriptive passages that are often irrelevant. This includes, in some cases, a rejection of a never-ending product line of supplements, and — in effect — building that all into the original game, so that it is expandable by GMs and players rather than more dependent on regular external support.

There have been major developments in designing tabletop RPGs for specific numbers of players. There are a bunch of 2-players games now, some 3- and 4-player games, and two that I can think of for 8 players.

Diceless and freeform tabletop designs have made huge leaps and bounds forward. This is something I'm personally very excited about. The approaches are often vastly different, from Stalker to The Quiet Year (to pick two post-apocalyptic games with completely different takes).

The OSR's revival / rediscovery / reinterpretation / reinvigoration of styles of play derrived from early D&D is a huge deal. Sure, it's not innovation in some ways, because it's bringing back older styles of play, but there are many new games that are now coming out of this movement that are increasingly innovative and bringing back an important branch of the family tree of tabletop RPGs.

Larp design is heading in new directions as well, inspired by contact with other roleplaying communities (perhaps most prominently those in the Nordic countries).

I could go on and on. Lots of very important work has been done and continues to be done. And that's just the stuff I'm aware of from the communities that I'm plugged into.

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Two other major developments that I only remembered when in the shower:

First, while many games still assume that the PCs are essentially a «party of adventurers» in the D&D / Cthulhu / Shadowrun / Vampire-coterie tradition, there are more and more that propose some alternative model or relationship between the PCs. This is still an area that needs more development, but we are gradually opening this space up.

Second, and this is really important, we are now past the point where nearly all games treat combat and magic/power mechanics as the core of the rules (including, as Malcolm rightly points out, things like social combat that are often just combat mechanics redressed). This is a HUGE DEAL, since there are now dozens of games that are not focused on violence (and, often, killing) as the central focal point of their rules. This is a much needed breath of fresh air and I hope it continues to expand and provide much more variety in terms of mechanics and game premises.