
Level5Dragon |

Hey, so I actually was playing with a very similar idea before. My plan was to do the same with the NPC classes but after a major event (read: families are killed by orcs in a raid)they set off on a small adventure, low CR like you said, and then level up to their first "Hero" level. Thus locking them into that career track. I think yours sounds very similar just obviously without real classes coming in.
To that, my biggest issue I had was BALANCE. NPC classes don't work well here, which don't get me wrong I like rolling for stats vs point buy so balance is not my main point. However, it does suck to be a commoner. Literally nothing is in your favor. So unless that player is cool with being the worst of the worst then it's probably not going to be picked.
My biggest tip is that while it's a good idea and I think keeping PC levels in but at a Slow Advancement XP track and having the level CAP be like 10 or 12 is a better approach. I went as far as even making some house rules that limited character progression to keep them "weak".
In the end if the players are cool with it and you like it who cares how it works as long as it works.