No problem.
The class levels things was in order to allow class progression and also to make it so people who have been in a class for so long are more proficient at the job. But the main point is so that adventurers can advance in different classes and unlock higher tier classes. Like Paladin like I described or Fighter+Wiz=Mage Knight or something like that, there's tons of potential things you could do and material to draw from for this.
Also like you said it depends on how you make it. The main thing that appeals to me for it is so that you can create actual party compositions (Tank/Healer/DPS) as well as have people that perform different functions (like the Scout allowing further distance from the guilds) and then have them partied up in order to allow adventurers to be specialized.
Having adventurers earn classes based on what they tend to do the most could be interesting but without having direct control/influence I could see this becoming problematic because most adventurers will tend to become the same thing (IE: No one would wind up a wizard because they are always moving around and fighting/having to return to places to heal/deposit gold and that sort of thing.) Ultimately like you said it all depends on how you want to do it because it's your game but yea just some suggestions! I love party management games and there's basically no/little idle games that do it well so here's hoping you create something fun to play!
Viewing post in Potential features in next update!
Ok, you kinda sold me on your idea, there are a few systems that need revamped or the whole idea of these are pointless, like combat is basically whichever has the better stats wins instantly, and to make a party system, like a tank take damage (or distract) while a fighter can get in and attack, then comes the problem of an overly one-sided party where the fighter would be the only one getting XP. There are a few other issues as-well, working on this would definitely take a while, but I’ll try adding it.
I just updated the game with some of the features like event referring, and fixes that bug you were having. Saves have been kinda reset unfortunately, something I had to change for the future of the game kinda messes with current saves.
I’ll probably work on some of the more technical or user experience things next update. Along with party systems, it sounds really fun and painful to try and make hahaha.