Here, I'll start off. I hope this catches on, and I hope we get good feedback from the community to the point where the developers will take notice (and perhaps comment!).

(1) I love tanking because I like getting into the thick of the fight! More specifically, I enjoy the responsibility of controlling the boss. I enjoy having to move or position the boss. This is essential. Without this duty to control or position the boss, tanking is just utterly boring to me. I can't stand STANDING in place and tanking. I need the challenge of knowing when to move the boss this way, or when to turn the boss this way or that way.
To that end, I REALLY WISH interrupting was a thing for tanks again! I want brutal swing back for my War! And I want fights to be designed so that I will need to use it at key points to avoid a tank buster. Please make this a thing. Perhaps add in like a marker to indicate when you need to stun even (Although, I prefer no marker, but a marker is okay too if the devs think this is needed help those who aren't so into being super alert during the fight). Maybe a giant "!" mark on the monster's head? I don't know. I just want to use stuns again.

The second thing that really makes tanking fun for me is being able to time mitigation. I really enjoy being forced to time a holmgang or an inner beast to avoid a tank buster. Active mitigation in the sense that it's timed is really fun. So for this, I'd like to make it so that tanks are encouraged to sit on meter, and challenged to decided when to use it for mitigation versus when to use it for dps. Right now, I feel like cooldown abilities not tied to meter are used for tanking, while meter is pretty much used for dps. To this end, maybe prune the number of cooldown/role action mitigation abilities? And force tanks to use their job specific abilities (which are tied to meter/resources) for mitigation. And then work the encounter so that a skilled tank with great timing can optimize his dps by selectively using meter. Slow down meter usage a bit - instead of building it up then dumping it as fast as possible. Make building it up faster, but make it so that its not bad tanking to sit on meter, but instead, a smart tank knowing the encounter will be able to time his meter usage precisely for mitigation or defense! Maybe make invuln abilities like holmgang tied to meter.

Lastly, tanking is fun because there's a dps component to it. I don't want it to go away. But I want the dps component of tanking to be, like the mitigation part of tanking, timed and not spammy. I like the idea of dps windows. Maybe rework tanking or design encounters so that there are a max number of dps windows open to a tank for any given encounter. So, let's say, for encounter A there's 10 possible dps windows open to a tank given that he perfectly manages meter, manages the generation of meter, manages the use of it for mitigation. So a perfect tank has meter to take advantage of all 10 dps windows. A less skilled tank who inefficiently uses meter for mitigation might only be able to take advantage of lets say 7, and down we go.

So, to this end, I guess what I'm advocating is against tanks always in dps stance (unless theyre off tanks). I'll leave it at that.

(2) I'm a War. So I'll talk about War only. For me, I like War because he tanks with a big 2 handed weapon, and he hits HARD. Also, I like War, because he HAD this berserker vibe, where he heals BY DOING DAMAGE. The sacrifice for greater dps, or greater burst dps, is that he doesn't have as much mitigation as a paladin. Right now, Wars have a ton of cooldown defense abilities, but most don't fit him at all thematically. That alone makes them less fun to use. I don't know what the proposed change would be, maybe like the OP suggested, merge the old bloodlust into unchained? That would be cool.

Maybe allow for rage generation outside of battle again? And then tie the new bloodlust/unchained to meter? Create some kind of tension/choice between the new unchained for steady, moderate over-time sustain versus the high mitigation but low duration of inner beast v fell cleave spam for dps? Something like that would be cool.

(3) Well, I kinda didn't stick to the format I laid out because I mentioned skill changes above. But I hope this was somewhat constructive.

Let's keep the suggestions rolling. I hope this becomes a good thread.