I like giving my EKs the magic initiate and ritual caster feats to give them extra spell casting options. This is an acceptable work around for me. The subclass should be kept as is.
Yeah, I think this is an issue caused by the idea that a caster should be able to do massive damage spells in order to be proper casters and really, Damage and Heal spells are pretty inefficient use of spell slots...Full Casters have enough slots that they can do that fairly freely, but if a half-caster or third-caster tries to specialize in damage dealing they'll find they only have enough fuel for a little bit of activity.
Even with Full Casters I usually want to use things that impact the circumstances of the battle or situation rather than just direct damage. But I tend to feel that Half-Casters and Third-Casters just flat don't have the fuel to have damage-dealing the main focus of their casting.
A dex-based Eldritch Knight with Mage Armor avoids the necessity of an attunement slot and extra weight at the cost of a spell slot. Longstrider increases base move speed by 10 for a long duration which is more effective than you might think. Protection from Evil and Good on someone with decent AC makes undead, fey, fiends, elementals, abberations, and celestials much easier to deal with.