The 4e community seems a bit dead.

[Kiero]

13th age is good, but there's not enough crunch for good theoretical optimization.

My group isn't interested in "theoretical optimisation", so no loss for us.

D&D 4e and 5e are very different beasts. There's little in each edition that would appeal to fans of the other one.

Indeed, there's pretty much nothing about 5e that appeals to me and mine, having come from enjoying 4e but finding it too slow.