Raskal is an 8 powered SOB. That alone makes him good.
He has poison and damage so is not completely crippled by SOA or DR if only one is faced ( almost all cards are weak against soa and DR combo)
He makes a 7 life gap which is a lot. You can play a lot of mind games because of poison.
Coleridge is useless against SOA, has 1 less life gap and is more vulnerable to heavy dr.