Can I add something else?
So I plucked the Gamma World 7e box (the one based off D&D 4e) from the shelf because the teenager group wanted to try it. I haven't played (or even looked at it) in around 10 years.
It all came back: the movement, attacking specific defenses, combat advantage, measuring blasts and bursts in shapes that worked for a grid, movement measured in squares, Encounter and At-Will powers, second wind, bloodied, recharge rules, save ends, ongoing damage, Solo/Elite/Minion categories, Skirmisher/Brute/Soldier/Artillery/Controller descriptions, easy encounter building guidelines, etc.
The design is intuitive. I doubt there are many games I could come back to after a 10 year absence and be able to run it with minor hiccups AND teach it to new players so it clicks.
Being neck-deep in PF2 for over a year (and 5e for the past decade), I have really missed how well designed 4e is. For my tastes, it blows both of them out of the water when you compare Depth AND Ease of play.
I wish WotC hadn't killed it so early, or at least gave us the ability to keep it alive outside of the restrictive GSL. It's the only edition of D&D that can't be OSR'ed, can't be implemented on a VTT, can't be enjoyed by new fans without searching out of print bookstores. And it's a shame. Likely it's a reason I have such a grudge against 5e.