I am a fan of the changes to blocking in regard to Stamina regen in principle. However, I feel that it affects players in a disproportionate fashion. Certain aspects of the game require tanks to block for the majority of the time if they are going to be effective... and by "certain aspects" I mean the toughest parts of PvE that are actually a challenge for players who have been playing ESO for a long time.
One way to address this for PvE is to reduce boss deadliness in a roughly proportional fashion to the blocking nerf. I don't think this is a good solution. The balance between player skill and endgame difficulty is pretty good right now. For those who care about PvE dominance, timed trials offer a pretty good incentive when they otherwise feel invincible. The game is amazing, and there is something for everyone. We don't need weaker bosses, AT ALL, as this would require a re-working of player DPS and Healing as well. Sloppy.
The negation of Stam regen while blocking throws all of this into turmoil. For PvP, I think this is a good thing. However, for PvE tanks who have been building and refining their builds for months and months now based on PvE efficacy, it is kind of a kick in the balls. So I am offering a way to easily address this disparity that works for everyone, since artificially making the game harder by diminishing the effectiveness of a role that has already had to redefine itself multiple times in a "trinity" game is not an elegant solution.
What if the Stamina regen negation while blocking were kept AS IS in regard to the update, but for every attack someone received from a taunted target, they were granted a lessened Stam regen negation while blocking... starting at like 3% % and increasing to 100% depending upon how many attacks were received from said taunted target(s)? A sort of reverse buff, and a gradual one at that. Start tanks out on an even playing field and make them work for their benefits while encouraging their group to support them. Then reward them for good play. Put a short-term reset on the effects of this: If someone is not attacked by a taunted target within 5s (or whatever time period makes sense,) reset the blocking regen buff. If they ARE attacked by a taunted target, add to it. PvP would not be affected at all because players cannot be taunted. In PvE, tanks would be required to block in a more situational fashion but would be rewarded for good play by earning the ability to block while regaining Stamina during long boss battles. By the time tough bosses go supernova, a well-played group would have a tank who could block much like they do now. Plus it makes perfect sense that a seasoned warrior can learn to fight an enemy more efficiently the longer a battle goes on.
Potential Drawback: Communicating this to newer players could be clumsy. However, merely telling them that "tanks can block more damage the more that they tank well" would be enough to communicate the idea to them. Indeed, even players who might be completely unaware of this dynamic would still enjoy the benefits simply because it operates based upon normal play styles for tanks.
TL;DR: Make taunting PvE mobs grant a reduction to the Stamina regen nerf in proportion to the number of attacks taken by taunted mobs.