Just a point about "irrational hatred of 4e"
The truly ironic thing is, so much of 4e appears in 5e without the slightest quibble, despite causing huge outcry in 4e.
Here's 5 examples:
1. The Battle Master Fighter and Superiority Dice. A Battle Master gains 4-6 Sup Dice over the course of his career. Now, I could, quite easily, spend 4 Sup Dice in a single round - 1 die for Feinting attack, 1 die for precision attack, 1 die for trip attack after the hit, and then burn Action Surge to take a second attack and spend one more Sup Die on another trip attempt. There, I've blown my Sup dice. Now, for some bizarre reason, until I rest, I've forgotten how to feint (and gain advantage) how to aim better (Precision attack) and how to trip on an attack. How is this not disassociated? Never minding that since this is a non magical character and these are "skills", I now have basically an Essentials Fighter from 4e. But, because it says 5e on the cover of the book, everyone loves it.
2. The Barbarian and Rage. When a Barbarian rages, he takes half damage from all physical attacks. Huh? How does that work? Suddenly I'm really angry so weapons bounce off me? What's going on in the fiction here? When 4e introduced this kind of stuff in non-magical characters, critics when ape. 5e completely gets away with it.
3. Attunement. All characters are limited to 3 attuned items. How video gamey is that? I mean, why 3? Why not 2 or 5? How dare WOTC tell us how many magic items we should have. They are stomping all over people's play styles by dictating how we play the game. Oh, right, this is done in 5e, so, it's perfectly ok. When 4e introduced the idea of "slots" all we heard were cries of "Video game!" and "MMO". But, 5e does virtually exactly the same thing, and WOTC gets a pat on the back.
4. Bounded Accuracy. The whole point of Bounded Accuracy is that the numbers don't really scale very much. A typical challenge for a character yields about a 60% success rate. So, the AC's for typical opponents fall around that range, save DC's too and difficulty levels for skills. It's 4e written backwards. Instead of everything scaling equally so that you always had around a 60% success rate for typical actions, they've simple done away with the number inflation and flat out given you a 60% success rate. It's not tied to the game and it's certainly not tied to the game world. 4e gets vilified constantly for this, while, again, 5e gets a pat on the back.
5. Healing Rates. While there has been some rumbling about the healing rates in 5e, it's been pretty low key. Despite the fact that 5e healing is virtually identical to 4e mechanically (while the numbers are different, how and when you spend healing dice are virtually identical) and you fully heal over night in both systems. Yet, again, we heard nothing but criticisms about how 4e healing was totally unbelievable and hurt suspension of disbelief. It was video gamey and the worst thing ever for role play. 5e does it, and other than a few die hards, you can hear the chirping of the crickets as far as criticisms go.
So, yeah, when Mercurous talks about the irrational hatred of 4e, I think he has a pretty strong point. The fact that 5e is getting pats on the back for stuff that got 4e vilified shows just how irrational a lot of the criticisms really were. People didn't hate the mechanics of 4e. They just hated 4e and used the mechanics as a scapegoat.