Dungeons and Dragons

That's a common way of putting down 4e, but it's not so. I have no interest whatsoever in WoW but I really liked 4e. 4e's approach was to build a very consistent and rigorously-defined framework for the game, and then build its various elements (classes, monsters, abilities, etc.) strictly within that framework. I think it actually hit a very nice sweet spot; the framework was sufficiently flexible that a huge amount of interesting and distinctive content could be made, but it was also well-defined enough and simple enough to understand and apply that everything "just worked." You could play as a fighter for a whole bunch of levels and then pick up a completely different character sheet for a wizard and you'd find that most of the mechanics worked the same. Combat was very positional, with lots of abilities that allowed you to set other players up for success, which encouraged teamwork and player interaction.

It annoys me greatly that WotC tried to set the system up to be dependent on their online tools, failed, and then tore the tools down to leave the wreckage largely unplayable. I can still play a 3.5e campaign just as easily as I did back in the day but it'd be rather hard to play 4e as easily even though I still have the books. The best tools were WotC-owned and they don't allow third parties to fill the void they left when they decided to transition to 5e - presumably to avoid another Pathfinder situation.