Double-post but it's substantive so I think it'll slide:
One note for the Naga Sea Witch issue: I'm actually quite sympathetic to this, and have thought a lot about how best to resolve such situations, and my solution has been a sort of exciting theory-crafting/mental design challenge (which I may someday put into practice). I haven't finalized all the details, but I'll post what I have below:
So the issue is, you want to use a Hero, but you don't require keeping the abilities as they are (functionally/mechanically), and you don't want to mess with the balance of the game as-is. If that's the situation, then you must preserve the mechanical function of the hero (it's stats, abilities, etc)... but you don't have to keep anything else, anything "non-mechanical". Preserve the 'Function' while changing the 'Form', as it were. I believe there are two primary ways to go about this; both free up the primary 'thematic concept' of the Hero (e.g. its name, model, texture, animations, icon, proper names, tooltips, etc), but vary in how in-depth (lol) they are, and whether you get to keep the abilities (thematically) as well:
(OPTION 1) Simply replace Hero 'theme', freeing up the concept of the Hero (name & model), while keeping abilities fully identical (Thematically & Mechanically)
//frees up just the Hero conceptually
(OPTION 2) Replace both Hero 'theme' and Ability themes (e.g. a complete Thematic rework for the Tavern Hero, maintaining only Mechanical/Gameplay fidelity)
//frees up both the Hero & Abilities conceptually (if reworked mechanically).
So for Option 1, you just need to come up with a new "hero concept" that would fit a ranged INT archer hero, with the standard skillset of the NSW:
-Forked Lightning
-Cold Arrows
-Mana Shield
=Tornado
Such a hero could be a Kul Tiran character, maybe a "Tide Hag" or an "Arch-Witch"? You could instead envision a sort of "Storm Elemental" (though why it would shoot arrows is a problem to solve), maybe? Perhaps a bow-wielding Orcish 'shaman' of the Stormreaver clan?
On the other hand, for Option 2, you really open up the floor for a design challenge. You now just have to design a Ranged INT hero (no longer necessarily an archer), with the following abilities (presented mechanically, stripping out all thematic elements:
-forked Direct Damage spell (possibly with lightning SFX)
-autocast "arrow" ability (+Damage & Slow)
-toggled "mana-for-life" shield
=channeling summon (mobile, Damage-over-Time vs. Bldgs, Slowing/Disabling (periodically) vs. Units)
Considering that you can change basically everything 'aesthetic' about each of these abilities (e.g. names, tooltips, SFX, concept) as well as the Hero, you can really go wild. Here's just one example I thought up (all placeholder names):
"Elven Arch-Sorceress"
-"Magic Missile" (replace lightning with regular missiles)
-"Bolts of Lethargy/Chill-shot" (instead of arrows, magical 'Slow' energy or maybe just 'Ice' element, augmenting her regular magical projectile)
-"Aegis On/Off" (same)
="Arcane Flux" (like a big black hole or arcane singularity or whatever)
And then of course, you get to have a "Naga Sea Witch" (name/model/icon/etc) with "Forked Lightning", "Cold Arrows", "Mana Shield", and "Tornado" in your faction (all with different mechanical functionality, though), without worrying about ruining the game balance.