[Sensori]

1) No, except the Const 8 weapons Sword of Injustice and Sword of Justice, and that crystal shield which gives 1 more holy in fights.

2) Not really. They have their uses, and they can be buffed up with items, empowerment, spells and such. Level 1 Water mage, for instance, can make a 1 water giving ring when you have Const 6. Also, you need at least Blood 1 to have a worthy blood hunter (if you give him a sanguine dousing rod, he becomes even better). Then there's that 1 fire giving 1F1D item. And so on. Also, they are usually cheap researchers, which is a good thing when you're also trying to recruit national troops early on.

3) Not much.

4) It is for blood-intensive nations like Lanka, Mictlan, (to a lesser extent) Abysia and such. Lanka and Mictlan have awesome national blood summons, too.