the heroes are simple, with no trait system other than 'has magic' and a list of vanilla combat stats. There are no special abilities.
They have special abilities. Sometimes two or three. They're just not that good, and you have no control over it.
B: no matter how complicated the unit creation gets, everything still boils down to that tiny little tactical combat map.
Not really. Autobattle happens a lot. Tactical for me is more about minimizing casualties, because autobattle doesn't account for magic, and vulnerable characters tend to get caught in the press and killed. Tactical battles are actually, in some ways, totally superfluous. But it can let you achieve victory when you're outnumbered with proper tactics. It's entirely standard for 4x games and fantasy battles. I'm not seeing it play out any differently than HoMM, MoM, GalCiv, or any of that. Tactical battles are almost always winnable by virtue of direct control over your best powers, assuming you're reasonable about not biting off more than you can chew.
the only terrain that matters are the special squares.
Again, not true.
Terrain has a huge impact on movement rates. Natural terrain barriers like water and mountains have a large impact on your strategy and expansion. (And you can modify them. For example, I cut about 25 turns off a caravan route by simply raising a land bridge across a bay between two towns.) Forests outside your SoI serve as breeding grounds for monsters, and you can use them to predict trouble areas and problem spots. And then there are a crap ton of "special squares."
There just isn’t that much unexplored territory with magic. Same with items. What type of item can you add that expands opens rather than just giving a larger pool to try and min-max.
Items have room to grow, and so do spells. I just find their initial approach, and their implied commitment to something really cool, to be really lacking. I love magic, deep arcane systems, and this barely even meets the level of depth or fun of MoM's magic. And MoM's system is neither deep nor arcane. And really, it's that no one was tried to do anything unique with magic in the video game sphere in a long time. I would have accepted worked up magic with lots of effects and power. But we didn't even get that in large measure. I STILL haven't found the volcano spell, and when I do, it's not going to make up for the dozens of hours I waited for something cool.
More options doesn’t really add anything to game play.
Blanket statement is blanketing
Options when they're done right and presented correctly add variety, customization and experimentation, and don't require a lot of detective work. I enjoy sitting there on pause personally, and actually thinking through mechanics to arrive at a decision. That's when I know a game has got me. If I can process what I can and will do without stopping, it's a shallow game to me.
In that sense, Elemental has got me. There is a lot to think about when you have three cities, two factions at war with you and are just about to up your adventuring level.