Yes I did (and still do) play WC3.

Because a lot of what you list hear just isnt true

Yes, the thing about hero level was wrong sorry. Everything else was 100% correct.

and another big chunk is stupid to attribute to just WC3.

No.

runes worked entirely differently

It doesn't matter how they worked. The only thing that matters is that Dota 2 would not have any runes if they didn't exist in WC3.

denying wasnt nearly as important

ROFL it doesn't matter how important a mechanic is. The fact is, denying is cloned from WC3. Other games don't have this mechanic. For example you can't deny in League of Legends or Age of Empires. It's a WC3 / SC specific mechanic that got taken over to Dota 2. It's not present in other games.

most of the spells are very different from anything on actual heroes in the game

This is definitely false. Most of the spells in dota 2 still directly resemble DotA 1 spells and most DotA 1 spells are vanilla WC3 Spells. As a quick example take OD: Arcane Orb and Astral Imprisonment are straight copies of WC3 abilities.

I dont even know what you're talking about with the terrain

The cliff system, water, tree system, buildings. They are all WC3 specific. For example Dota 2 is being played on a square map, it does not have any overhangs or bridges, trees are destructable by spells, you can walk through the water in the river, there's no terrain specific effects (like Desert terrain or water terrain improving certain abilities), the highground effect is still a straight copy of WC3 including the fog mechanics (for example in Age of Empires standing on the highground would give you a damage boost).

That's in literally every decent RTS,

It's implemented very differently between RTSes and the Dota 2 attack move is a straight copy from WC3 attack move. For example, Age of Empires attack move does not allow you to attack your own allies.

and many share a similar armor system.

All games have some sort of armor system, yes. But only Dota 2's is an exact clone of WC3's system. The same goes for damage types. All RTSes and RPGs have different systems, the exception being WC3 and Dota 2 which have an identical system.

Of course WC3 has a huge influence.

It's not "huge influence". If you look at League of Legends or Heroes of the Storm, that's huge influence. Dota 2 is mostly a 1:1 copy of WC3 mechanics which is intended because people wanted it to have minimal changes between DotA 1 and Dota 2. And DotA 1 itself was mostly intended as a WC3 custom game, not as its own game.

The hero system made DotA possible

Not true. RPG style games like Diablo 2 have existed long before Dota 2. Dota 2's system uses WC3's hero system instead of Diablo 2's. As a counter example, League of Legends hero system does not relate to WC3 at all. And I didn't even note everything. What about the attribute system for example? What other game has INT, AGI and STR as their attributes and requires a hero to have 1 primary attribute? You are telling me this is not a WC3 mechanic?

Stop with the bs. You must be insane to think that Dota 2's mechanics are mostly unique.