Why doesn't pve have pvp combo structure?

[Rilifane]

Pressing separate buttons adds an additional layer of execution the game sorely needs. Most content is already braindead scripted, imagine having to do it while only pressing one button over and over again. People already rejected the changes to healer that have you doing just that.

We might as well put one button on DDR mats or guitar hero controllers at this rate.

Next people will be asking "why cant we just automate the game?".

The basic 1-2-3 combo of every class is pretty basic and mostly filler between bursts. It's the first one you get, the first you commit to muscle memory, it's easy and straightforward and generally the least punishing to mess up. Freeing up buttons means they could add more interesting (and punishing if messed up) skills to the rotation. But these basic combos contribute least in terms of difficulty and are as close to pointless button bloat as it gets. The two follow ups from DRG at least have two different positionals in quick succession, but the two 1-2-3 combos before that are once again as basic as it gets.
I completely understand why people would rather see them (and skills that are mutually exclusive) consolidated into a single button to make room for more interesting skills. Of course that's all under the assumptions that we won't simply get as much as possible consolidated without getting anything in return.
Mudra, Blood/ Life cycle, Third Eye are interesting mechanics that add a layer of difficulty and make room for optimization. I'd trade 1-2-3 for more of that any day.