Laurefindel
Legend
... or like a ranger, who is also built on the same frame and yet fill distinct roles (although hunter's mark does not compare with divine smite IMO, even if they both are "spend a spell slot to increase damage" features). If there is room for a ranger and a paladin, there should be room for an arcane-d10-halfcaster-extra-attack-at-5th-level-class-with-class-exclusive-spells..Sounds like that's just a Paladin...? Some of this seems to be investing in a "Arcane"/"Divine" dichotomy that doesn't have much of a basis in the ga.e, other than some fluff. I just don't see the mechanical design space nor the conceptual trope space, with all of the various Gish solutions already on offer.
Maybe I should say there would have been room for an arcane paladin/ranger if it weren't for the eldrith knight, who would probably become redundant, just like a divine third-caster fighter sublcass would likely have a hard time distinguishing itself with the paladin.
The eldritch knight could (should?) have been a class of its own, with bladesinger (and maybe even artificer) as subclasses.