So you've essentially admitted that for two full years D&D players had to play "slogfest" combats using 4e's rules as written.......
No. I've admitted that things have improved. Even before the MM3 math revision I never found that there was a slogfest in heroic tier if you gave the monsters motivations and avoided certain crap monsters (which regrettably included most solos). Of course every edition has crap monsters (1e fewer than most although it brought us the flumph).
I think 4e is the only edition of D&D in history where literally every monster manual has been a significant improvement on the previous one.
Monster math and skill challenge math in the original release of 4e was downright shoddy and broken--even the developers admitted it, though not in so many words. Being forced to defend a system that took two years to get the internal math correct isn't a point in that system's favor, IMHO. In very few industries will a company survive by making consumers wait that long for a working version of its product.
Good job that the math of 3.0 was correct on launch then. And we've never had a 3.5 revision two and a half years later. Or a pathfinder revision. And these have all been perfectly balanced.
Also it's a good job that Gygax didn't seriously have to power up the 1e fighter significantly in Unearthed Arcana
six years after he released the PHB.
In fixing the math, 4e has been
amazingly fast by historical D&D standards. It could, however, have done with a lot more playtesting than it received; they threw out Orcus in 2006 for being insanely complicated and started over (and what's left of Orcus became the Book of 9 Swords - in Orcus literally every class had a different recharge mechanic, and there were at least half a dozen different codition tracks).
You can defend 4e for doing a lot of things right; the baseline damage math of the original product release isn't one of them. And expecting playgroups to hang around for 2 years while the math gets "patched" isn't a winning formula for success in today's market. If the baseline math is broken in 5e, I can guarantee I'm not going to wait around for two years for Mearls and Co. to fix it. I've got way better options for my RPG time than that.
Do you play 3.X? 3.X/Pathfinder's math hasn't been fixed after
twelve years. And when I looked at the idea of playing a Summoner I realised that the summoner I wanted to build could outsneak the rogue using the Eidolon, outfight the fighter using Augmented Summons, and out utility cast a sorceror due to a very nice spell list and not having to use top level slots for combat due to opening most fights with a Summon Monster.