Beeing a regular TB Player I have to disagree wholeheartly!
As fire TB 1 vlamish guard is the only thing you need for mana reg.
And as ice TB you just save up for HoL.
I'll be damn honest, I don't see how anyone plays any class with only a Vlemish faceguard. I hear it all the time "Vlemish Faceguard is so op, it is the only mana items you need!" I have played TB and Regulus extensivlely online as well as most the other classes extensivly offline and I don't see how that is possible. Most heros (with maybe the exception of Oak) are so mana intensive, I end up needing atleast two mana items if not for favor items.
I think a lot of people tend to over use their mana abilities. TB's who like to ice down waves of creeps a little TOO much, and don't know to swap between forms to keep their mana up, Rooks who hammer slam grunts, Erebus' who like to mist while building an army, etc etc.
The more you play, the more you tend to release your mana abilities in bursts, while conserving it otherwise.
.... Or maybe people just play on Leviathan too often.