Reputation and WQs are a nono for me, I hated every single part of it, logging on JUST to do Nightfallen dailies when I had to catch up... was stupid.
I don't mind traditional rep grinds, farming stuff to give in for rep, or even just quest lines for rep, but GATED quest lines with GATED rep, ugh. never doing it again.
I don't mind titanforging, ONLY if it goes back to what it used to be near end of MOP (Not sure where you got end of cata from...?), Started with Thunderforging if I remember correctly, then "warforged" IIRC in SoO... I didn't mind these, as they were a FLAT base upgrade, to the normal item, not "anywhere inbetween 15-40" Etc Item levels..
And as you say, Gated progression, I don't mind it, but if it's storylines being gated, and then it takes 1-2 hours to do the storyline just to unlock more WQs for rep for gated content, yeh, im not doing it, i'll do it once on my main, and my alts can just deal with not being on Argus for example, I have 10 level 110's that want to be on argus aswell as my main, I don't want to go through 10+ hours of content I HAVE ALREADY DONE just to unlock content I have technically already unlocked. (People will say "well you leveled all of these, how come this bothers you?) to answer that, I like the old content.. They said that alts will unlock the WQs when their main has completed argus, well, that hasn't happened, woo.
my main complaints in this expansion is weapons, and alts, I love my alts and always want to play them, but I also loved back in the day getting a new weapon, for me, it was the "main" piece of the gear. In legion its like "meh, a relic, ok?" Doesn't excite me as much as say, getting a PvP weapon that I earnt, or finally downing that boss to see that weapon there I can /roll on etc.
And Alt wise, well, this expansion just hates them, apart from 7.3 they have made it a little easier for them, possibly 2 weeks out of farming originally lol, as AK knowledge (depending on ur main) could get u to lvl 40 anyway... (even then it was only 4hrs per one... to catch up to 40 in the first place!).
So they havn't done much... I like what they have done with PvP Prestige system, but hate the fact that Ilvl is all that matters in pvp now, its like asking for Gearscore back in the day for WOTLK. Higher ilvl = more damage, and not even at that much of an increase, u barely have to try now, and even that, its only "tmog" gear I can gain really... less I get Titanforged :/ Aiming for RNG WOO! Bring back the honor system, 2 sets of gear (honor gear and Conquest or w/e it was) make the conquest better so its more powerful, or a set bonus 5/5 so when u get it, your stats increase by 10% or something so you ACTUALLY feel powerful, that upgrade when you get a full set... but keep the prestige system...
Dno, theres lots of things in this expac lol that ALOT of people hate I loved the WQs at the start, now I hate them etc etc list goes on