It's always the same scheme blizzard designs expansions. It's always the same mistakes they repeat at every start of every new expac, without any chance to ask them to change their design paradigms.
1.) At every start of a new expac, make healing and mana regen awkward.
This has been very bad in cataclysm, it was nearly same in MoP, and it will be the same in WoD. With starting gear, your manaregen will be low close to starving, and at the end of an expac, mana regen will allow healers to overheal and cast the most expensive heals over and over. While i doubt that blizzard would ever manage to balance this correctly, i even doubt they want to balance mana consumption that way it wont change much during an expac. Probably the best way would be to disconnect mana regen from gear progression, and to put it on a level thats working nice with mindful healers from the start.
2.) At every start of a new expac, classes are weak. And the end, they are strong.
Which is not only based on gear, but also based on a permanent buffing of classes thruout the expac. Instead of nerfing raids, blizzard just took the approach to buff classes thruout an expac, to make old content more easy. Instead of this awkward approach, classes should stay the same power, and only be able to add power by gear progression.
3.) Blizzard adds special gear for every game component.
Instead of diversity, often there is only one single way to acquire gear. You only get tier sets from (organized) raiding, you only get blue sets and pre raid gear from dungeons. And most times, there is no alternative to gear up using different approaches. For the very first time heroic dungeons will be an alternative to LFR, which infact isnt the case, as gear from LFR still is more powerfull than heroic dungeons. At the end, people will run LFR for the gear they need to start raiding and fill it with heroic items, if their skill level is adequate. A way better approach would be a diversified way to gain gear. I think that no matter what you do you should be able to gear up, with better rewards if its about challenging content, which blizzard always mixes up with the level of organzation. The level of organization is the main brickwall for players to play challenges nowadays, and i am sure that single player challenges would add a lot more ways to gear up instead the need to organize, which is a mindset from 2005, but surely not 2015.
4.) Blizzard adds a time sink to every start of their expac.
At the start of an expac progressing just feels 100 times more awkward than at the end of the expac. Just think about those mandatory dailies in early MoP, which lead to a massive loss of asian players due to the time demand. Blizzard always arguments those timesinks with scapegoat arguments, as like in the case of the removal of flying in WoD with the idea that people could skip content (which they also may in WoD without any problem). While it infact is just about the additional time spent with travelling, which will stretch the content to a large degree. Another example were the 5 mans in early cataclysm, which were a brick wall for every player, no matter, if players liked to play challenges. Blizzard adds a brick wall of this kind to every expac. They did that in TBC with attunements, did that in Cataclysm with hard 5 mans, and did that in MoP with mandatory and dull daily quests. And they will repeat that mistake in WoD with removing flying, at least temporarily.
5.) Blizzard bases design decisions on logic arguments
Whenever you talk to blizzards customer support about changes and if you disllike them, they ask your for logical reasons for changes. It seems to me, that the "collaborative" design for WoW is based on logic only, while that is the complete wrong approach to base design decisions on. Logic probably would lead to a logically designed game, a game Mr. Spock surely would love, but would it be fun for those humans like us, which actually want a funny game and not a "logically well designed" fun place for the WoW Devs?
It's a game. Its about fun. And not if removing flying is logical. It also would be logical to remove mythic raiding, as only a very few play it. Still that wont happen, as its about preferences at the end, and about the subjective idea how a MMO should be.
6.) Blizzard only knows extremes
Really, i never had to follow as fanatic people as the blizzard developers. They either switch something on or off. There is nothing inbetween.
We want dailies. So lets add 100 of them to the start of MoP and make them mandatory!
We dont want dailies. So lets remove them all and dont think about adding even one single daily hub anymore!
We want flying. So lets make content for it, as like Sketties.
We dont want flying. So lets disable it once and for all.
What blizzard really should have done about this would have been to find a balance in design. Something blizzard never learned. To find a agreement between position 1 and position 2. And not either on or off.
7.) Blizzard changes running systems
One of the main mistakes is blizzards idea to change a game just because people want changes. I really doubt that people want to remove running systems. If i should give an example, i would bring up reputation from dungeons as example. It was highly replayable, and very convenient for alt players. Still it got replaced by a solo player grind in MoP. I could also bring as example removing flying, which was, from my PoV at least, a running system as well. At the end the complete discussion about the fact blizzard removed flying destroyed way more than the gain ever could be, as the change itself splitted the community.
If blizzard would get rid of all those mistakes, and just design the game with the most fun experience in mind without all those extremist decisions, without all those timesinks and class design ideas at start differing so much from at end of an expac, WoW could become a real great game again.
I am not really seeing blizzard changing at their paradigms to design the game. They will continue to repeat the same mistakes over and over, and there will just be no chance to ever convince them to go a different way in designing the game.
Thanks for reading. And tell me if you think blizzard should change this behaviour or if its right to continue their path.