yeah, sorry dude, your list was countered, that doesn't make it OP, just means you were probably too focused on one thing if this tank ruined your whole army. This is the sort of thing that should be encouraged as it shifts the meta and makes it harder to predict what one thing will be good.
Thats why I think FW should be allowed as standard, that and you know, the rules saying it.
Its AV 13/12/12 doesn't have any effective way to deal with anything with a decent armour save or anything dedicated to hurting tanks.
Its main guns are great at taking down skimmers, yes that hits Eldar harder than most, but its expensive and not invincible.
Also it looks awesome.