I concur, the nature of FFXIV's "Proactive" combos means you know exactly what you'll be doing for the next 20 minutes in any fight. If you get rid of the main 1-2-3 you'll literally be playing an idle game in PvE, where fights are scripted and you know *exactly* what your opponent will do next.

PvP is a different beast, because you're not trying to beat yourself, you're trying to beat another person, so simplicity of toolkit is a boon.