Combos used should have nothing to do with it. Every serious player should always be going for what's most efficient and gives the best dmg/setups etc. There's no point going for flash. Also, the strats you mentioned only work on a few match-ups. Sub can't just Clone whenever and be sorted. You actually have to be very strategic with the Clones (especially as they're quite easily punished by a fair amount of the cast). You may as well say that Ermacs just spam TKP, Kabals only use the f+3,2 pressure strings, and Saibots just spam Clones. It might look like that to outsiders, but there's far more to it than that.
Trust me, I understand that. But there are many characters that can take many setups and turn them into big damage. Cyrax, Cyber Sub-Zero, and Skarlet to a name a few, have a large variety of combo setups for big damage. Whichever the player choses to do is based on A: the difficulty of the combo, B: the setup/opportunity presented, C: their own knowledge of what's most efficient. Either way, you are guaranteed to see a lot of variety in their gameplay as you go from player to player. This is not the case for Sub-Zero because he only has a handful of setups and combo directions. He is very generic compared to many members of the cast.
I never said Sub can clone whenever. Obviously these strategies are applied when appropriate. But that's still essentially the crux of SZ' gameplay - hiding behind clone, dashing in and cloning, trapping people in the corner with clones, making combos safe by ending them with clones, B+2 resets/enhanced ground freezes, and trading projectiles as needed.
Note that I'm not saying Sub-Zero is bad, just boring to watch. He's just generic and you won't see much gameplay variety between players. He more than likely has few or no discoveries left, so yeah... every good Sub-Zero DOES play the same.