The Legion style of tanking comes across as a sort of "correction" of community problems when it comes to tanking. The two main problems are
1) Tanks "don't require healers"
On current content in raiding tanks require healing. This usually crops up when tanks badly overgear encounters (exacerbated by item level upgrades). I know I pretty badly outgeared Xhul when my guild was progressing on it since I was ignoring my 4 piece and was using Mirror of the Blademaster instead of Warlords Unseeing Eye. That said, even now outside of stupid speed kills I still want that row of HoTs from druids, the paladin beacon healing, and disc priest absorbs. My problem with the attempt to "fix" this problem is that I think it should've been swung at from the healer end first and then worked from the tank side since you might've seen a close to 50/50 split during early progression when people weren't geared out to the teeth. You've also got to consider the massive amount of passive healing and absorb healing going on right now. Depending on tank and that specs style of tank I don't think that's a bad thing though and usually to get those long periods of "no healing needed" you'll need things like large cooldowns and external cooldowns anyway.
How "fun" tank healing is is pretty subjective, but unless you really like the idea of a designated tank healer in raiding (something they've been trying to yank holy paladins away from or at least make them more versatile) its the direction they're going. Part of this problem actually stems from there not even being enough raid damage to heal so when healers go for scraps they go to the one(or two) players in the raid that will always be consistently taking damage: the tank. When you've got several healers fighting over that competing with Beacon, Absorbs (which are a problem all their own), and just HoTs from every other healer its going to look like the tank doesn't need healing.
2) Tanks "do to much damage"
MoP you could do some silly things, I remember being the top dps by a good bit solo tanking our first (and only) kill of heroic 10 garrosh because of it. WoD reigned this in and I think the damage values in Highmaul were decent enough. Tanks had ways to dump resources or trade survival for more damage. This is a community problem in that you see the top tanks doing some great damage and then people start requiring their group's tanks to do the same when they may not be comfortable enough with the fight or even have the group/ability to do the same. Trading your resources for offense over defense insured that when you did use your defense it was more important when you do (you had larger periods of vunerability) and it had the added effect of making tank healing more relevant (passive or otherwise) because you were going to take more damage regardless.
Forcibly removing this obviously negates the ability for the community to force tanks who simply aren't ready or capable of playing to the level and coordinating with healers to go this next level. This is also somewhat subjective depending on what you are trying to get from the game as it could be argued this not only affects personal gameplay, but the team aspect of coordinating with your healers to make better use of their healing and external cooldowns (which for the record I'm not a huge fan of external damage reduction cds). They're obviously removing a problem (although others will crop up in its place probably), but you're also stripping some people of gameplay they enjoyed and reveled in. The aim is clear, but we won't really know the full results till later in Legion itself.