Arcane vs. Divine isn't really a rules distinction in modern D&D: magic is magic, fluff us a Class/Subclass level distinction. It was asked earlier, but what is the literary/cinematic archetype here?
The ranger has a forester/summoner theme, slightly ranged-oriented
Paladin has a leader/healer theme, more melee-oriented
Gish (let's call it that for the sake of this discussion) could have an elemental/conjurer/evoker theme, melee-weapon and ranged-spells oriented.
Just as some ranger and paladin subclasses focus or depart from certain elements of their basic archetype, so could the gish with an arcane archer subclass, a light-armored bladesigner, a defence-heavy abjurant warrior of sort, a mobility teleporting skirmisher, an offensive elemental strike subclass, etc.
I'm not saying that's what should have happened, only that it could have happened that way with an arcane half-caster built on the same frame as a the paladin with enough variety to each give their own role, niche, and function in and out of combat, just like the ranger and the paladin differ from one another despite also being built on the same frame.
Personnally, I'm fine with refluffing the paladin saying "screw this honor-code, righteous, holy warrior stuff, I'm a warrior-wizard and don't want anything to do with religion!", or refluffing the artificer saying "screw this science-technology gadget concept, I'm a savage warrior with an ancient runic tradition", but I know not everyone see classes as grab-bag sets of abilities with a suggested theme.
[edit] and I would be ok with an even fighter/wizard split if it weren't for waiting until level 5 to get a subclass, level 7 to get an ASI, and level 9 to get extra attack. Many multiclass concepts work very well at level 10+, but it's level 1-7 that interest me most. For that, the paladin and ranger frame fills the gap nicely.