Note: you mixed up Intervention & Intervene, Intervene is your gap closer, Intervention is your target sheltron

Positives:
-Holy sheltron, I like the barrier over just having two mitigations, I also like that it can target party members instead of using intervenetion.
-Intervene being eariler... don't think its needed at 10 but i wouldn't complain lol.
-I like the idea of gaining attacks upon blocks. maybe the idea needs a bit more work though
-DOT combo was a lot more fun.

maybe/confused
-Would the combo's shield's stack or just over write each other? i can see this as a downgrade if you're not taking any damage at the moment, but if it were to stack i think that would be also too strong...
-I like cover granting you blocks but i dont think it needs to cost gauge.

No thanks!
-Sheltron costing 25 gauge & more things on gauge im not a fan of, bulwark changes also seem kind of odd.
-Passage should stay 120.
-arms ehanced seems op...

Theirs some interesting concepts out there, I personally really would like your sheltron changes DOT combo was also really nice (just had issues with how burst meta worked)... some things seem a bit confusing or too powerful though.