It's funny to me, personally, that you use World of Warcraft as an example and say that it lost "a ton" of players. I know personally I couldn't even stomach playing WoW before Wrath of the Lich King (and I bought Original when it released) because of how incredibly exclusionary the gameplay was if you were not in that top 5% . It really had nothing to do with time playing (I played JRPGs most of my young life, so I knew what it took to spend hundreds of hours on a game). I had no interest in committing 40 hours a week to preparing to play a game for 20 more hours that weekend. I feel THAT is what has been addressed by Blizzard, and save the nostalgics and the elitists (who I feel are similar to those on these forums who gripe about special skins not being so very special), no one has much of an issue with needing to do less mindless grinding to experience the actual purposes of the game.
Another example I can give you is Super Smash Brothers-- I actually played in the competitive scene of SSB for quite some time, and experienced the bridging from Melee to Brawl. There was much crying and gnashing of teeth at the demise of "wave dashing" and "true combos"-- those combos that, if performed correctly, resulted in instant death. While a few hardcore players refused to budge from their "more competitive" SSBM, a HUGE majority of players adapted to the new SSBB, and I would bet that the upcoming SSB will have just as dedicated a following.
lastly, I think it's a little bit condescending to assume that game companies DON'T know what we want. They spend hundreds of thousands, sometimes millions of dollars to LEARN what we want. The problem is that sometimes what the general public wants isn't what is best (see: Tragedy of the Commons, Paradox of Value, etc). And unless you have a vision for your "art" (be it TV, games, books, or anything) it can get lost in pandering to the lowest common denominator.
I think sequels or new takes on old games need to have some departure from the original to have a need to exist at all. The first thing that will happen when you do this is that your current hardcore players will shout doomsday of how removing X (wavedashing/Conc jumping/denying/door hacking/AWP price/etc etc etc) will ABSOLUTELY DESTROY your game and you fail as a company and are out of touch.
I want to go on record to tell these players to knock them ****s off. Time for some real talk
Hardcore players, this feedback is not valuable. We know what happens if developers are too swayed here - you get new versions of an old game that has just enough difference to not pull you over (CS:GO, really the AWP cost being the same was important? No.), but not actually advance the series or genre in a meaningful way. Doing this disallows you to actually give the game any meaning - why does it exist, who is it for?
Now, developers have a responsibility here too; deconstruct why they're saying what they're saying. Many times, your hardcore fans want to ensure the new game has depth and skill. If you're changing how that's done, explain this process to your hardcore dudes. Don't pander or cave, just be upfront. If you're removing burden of knowledge/etc (things that most extremely hardcore gamers will latch on to as meaningful skill), be honest with it and try to evaluate that you're adding real skill mastery to your new game as well.
Your hardcore guys are valuable, but be careful to not let them rail your new game into total conservatism.