Basic stats to look for on a main tank are as follows:

28k - 30k health (30k is a good marker for tanking as its high enough to take the hits but not to high where youre wasting points into it where they could be more useful in other stats such as magicka or stamina)

17k+ mana (having 17k+ mana is a number you should aim to be at or to improve upon though is a good base number)

25k+ stam (like mana having 25k+ stam is a good base number, going over would be fine but try not to go under it)

If a skill bar is not made for a fight such as the first boss in vMaw it is because there is no need to change bars for that fight.