With the changes you suggested it is literally reduced to just that. Instead of burst dps moments we will get burst enmity moments. Using your example for SwO being a passive and ShO being the said buff. It's very similar to how healers utilize their cleric stances, which is not a stance but a cd now (was a stance back in ARR days) to deal damage during certain moments of a fight like pulls or add burns but with tanks it would be for enmity.
Now if we go to WAR, my main, some of the changes you proposed seem off to me. According to your description Deliverance is now a trait therefore it is a passive 5%, Defiance seems to function the same; turn on/off for enmity (like pvp), Unchained being a buff on top of defiance but shorter and higher potency and Beast Mastery being a trait does what we currently have when in our stances, which is to build gauge when using actions when under Deliverance/Defiance but without having it active? The wording is a bit confusing because if Deliverance is a trait it would always be up and can't be turned off.
Apart from this being very similar to how we have pvp currently it still further sets a precedent that tanks are just dps with higher hp and defensive values. You can't have high enmity tools and dmg potential without messing the balance of the game, which Yoshi seems to be very adamant about despite some classes clearly offering more than others, ex WAR/PLD with party shields and DRK with solo shields.
I went through Seal Rock in 3.0 before the nerfs and WAR's were quite literally what you described them to be. Always started in Deliverance and only used Defiance when needed. High hp with little to no dmg penalty due to Unchained when in Defiance and Berserk when available. I would FC healers to death and dps couldn't lay a scratch on me while I FC them to death. The point being is that I did little of what is expected of my class which is to protect my party and I just FC everything that moved because I can since I dealt as much dmg as the other dps and took much less dmg too. There was also a time when WAR's were nearly matched in dps to other dps in raid content and you would see them in the top 3 spots of rDPS because they had 100% up time on the boss. SE quickly remedied this.
This goes back to my argument that the game design is what makes tank stance useful and I strongly believe if bosses dealt more dmg tanks would stay in their stances more often. I'm all for making tanking fun, accessible and unique but making them glorified dps is not what I and others signed up for. Seeing 0 dmg from Omega's delta attack is just as rewarding as seeing dhcrits deal more than 20k from a FC. There's a reason why tank queues are instant. The responsibility, and consequences are much greater than any other role, not to mention the amount of flak we tanks get in pugs or pf.
A decent party can carry dead dps, a great party can carry dead healers but no party can carry dead tanks.