EK is just a crappy wiz/fig multiclass imo. May as well level a figher to 4 to get a decent base then level a wiz from then. Little bit like the arcane trickster although mage hand of legerdemain is pretty dope.
Personally, although it is against the rules, EK learning all the low level Abjuration and Evocation spells isn't going to make EK OP in anyway as they can only cast a few before long rest. Would make the class more versatile I guess. You can (swap) memorise a new spell at level up which is all well and good but at max level you kinda have to stick with what you got. If wizards can learn cleric spells in DOS&D....Sure let them eat cake.