Do you think you could really build an effective and deep combo system out of something like that?

I'm no game designer, but I can think of some situations and dungeons that would require such thing.

He wasn't talking about that, though. He was just talking about having a more complex, combo-based hack-n-slash battle system.

Unless you're just talking about a trick weapon system as a way to make a deeper combat system without needing combos. In which case, I'd be open. Though I don't really think any of that is necessary. Souls games, even Bloodborne, have incredebly simple combat systems. The reason they're so good is because the movesets weapons offer are so varied and more importantly because the enemies are well designed in terms of working well with the moveset the player will have.

Zelda already has a strong foundation for a really satisfying combat system. All it needs to do is design it's enemies better to capitalize on Link's moveset and arsenal. Wind Waker did really well in this when it came to enemy design forcing the use of many weapons in combat. TP did a good job of expanding Link's moveset. For a really premium combat system, all that would need to be done is to combine both. Make enemies designed to take advantage of Link's moveset, think Dark Nuts in WW but more, and also make enemies meant to take advantage of Link's varied toolset, think Peahats or Armos in WW.

After that, it's just up to intelligent enemy placement. A lot of people berate Zelda 1 for being "too difficult," but it particularly excelled at this. The enemies don't have to be extremely difficult by themselves, but being put in a confines area with the right assortment of enemies would create for an interesting, yet still very uniquely Zelda, kind of challenge. It also obviously doesn't have to be Zelda 1 hard or Bloodborne hard to make this possible.

Combat was almost perfect in Skyward Sword. Too bad Nintendo refused to wiimotes.

But that kind of synergy between both systems would require a full-revision of the standard combat system. A lot of things would have to change in order to implement the weaponry + moveset + adaptative enemy, considering most of the enemies in general only react to one kind of approach (Haven't played Skyward Sword, though I haven't heard great things about the required precision for some enemies); and at this point, I doubt it will be the case in the final product.