I am not sure how a game system such as d&d can avoid having a mastery of the system, the point to features of a class is to shift the probability of success for certain actions (if not outright make it so you character can not fail in a given action i.e. rogues reliable talent). A person who plays long enough will pick up a few tricks to shift situations in their favour. It sounds like you would have to strip many features that affect probability of successfully completing tasks so it becomes purely about what you roll on the dice ergo luck (and even then mastery of a system would make it so you would take the most efficient actions to avoid wasting resources, putting yourself in danger and maximising the potential outcome through better choice making).
Instead of denying your perspective, I ask how would you achieve your vision mechanically?