Tanking as a BLU feels nothing like the other tanks, it feels like you are a DPS trying to cheese a fight with a broken move. Healing feels like this too. Because both roles are ultimately a DPS, their respective toolkits aren't as strong and the entire dynamic of the group is trying to compensate for this. Something as simple as a tank swap can require group coordination. It's more akin to trying to solo old content or taking 8 PLDs and trying to do old raids synced, it's the same fight done with additional challenges and considerations that make it fresh. Just because aetherial mimicry exists doesn't change that.
To show you what I mean I'll even point out specific examples:
- the only tank mitigation has a cast bar and high MP cost. Tank needs to manage this carefully.
- Tank damage is nonexistant, which is a game changer in a culture of FFlogs and parsers, and means that BLU tanking feels the most like a tank that the role has had in a very long time
- Raise has a cool down so the group needs to coordinate in the event of death
- no oGCD healing, meaning - like the lack of damage on tanks - healers are primarily healing, far more than their regular counterparts. The lack of strong heals also means heavy communication between the tanks and healers when it comes to certain damaging mechanics.
Do you maybe want to elaborate on what you don't like about BLU and why it would be so bad that BST is like it?