Zardnaar
Legend
Casting Shocking Grasp or one of the SCAG cantrips is almost as effective as casting Eldritch Blast. At higher levels, Warcaster will give you an OA that makes the melee types envious, and that seems to be intentional IMO. Also, Eldritch Blast isn't a great option unless you have some way of canceling the disadvantage for casting a ranged spell in melee. A bladelock with Booming Blade is a better choice for an OA, IMO.
Polearm master feat, cast at 10'. This came up a while ago on the WotC forums as the abuse with EB was spotted very early on. RAI Polearm master should not be allowed and IIRC EB can only be used via warcaster at levels 1-4. Once you get the 2nd beam it doesn't work.