Even in a game of Commander, thisll do a lot of damage very quickly, and there are lots of ways to use those exiled cards, like Oblivion Sower, for example
Most lords buff power and/or toughness of other elves you control, and thats the classic definition of a lord
If WotC raises their prices prior to release we will give you the option to cancel without penalty or pay the proportional difference
Llanowar Elves approaches that mark as well
At minimum it's 5 mana and an attack trigger towards the specific player, and unless your engine is churning already your Elves may well not be big enough to kill the thing you want dead, or to survive the ensuing combat
A blue card is any card with a blue color identity, typically identified by its blue mana cost or a color indicator