Ok, I realize that this is almost certainly one of those things that will be worked out further once beta hits, but, I'm curious what your guys' vision is here. How will the leveling scale? By that, I mean, how much harder will it be to go from level 4562 to 4563 than it will be to go from level 3 to level 4. I know some games raise the amount of EXP needed for each level exponentially (or close to it), but, in this game, with the virtually unlimited levels, that could really bog the game down. So, how do you guys envision the differences between levels at this point?
Actually this is pretty "final," at least pending more playtesting in beta; but in our playtesting thus far it's working out well. I think the highest level I've directly tested with is in the 40s, though, so if balance later becomes a problem that may need some tweaking.
Right now the character/enemy stats scale close to linearly. However, there's a base 1-10 aptitude for each stat, and that gets multiplied by the linear value. In practice this means that a character who is "good at magic" versus "has a lot of health" is far less different from one another right at the start versus later into the game; those choices start mattering more and more.
When it comes to EXP gain, most of the time we're basing that on your civ level versus the level of the boss you just killed. Regular enemies (that you can farm) grant no exp. Other sorts of world improvement activities also grant exp, but the details of how that translates to your relative level is something we're still fine-tuning. Right now turning in a profession book is something like 1/12th the EXP it takes to get from your prior level to the next. So that stays a relatively consistent gain throughout the game now, but I'm not sure if that will become too easy to farm late in the game with lower-level areas. Still more to tune there.
But anyway, bosses: when you kill a boss, your exp gain is again a percentage of what is required fOr the next level (not remaining amount, FYI -- total. Just in case anyone was concerned). The percentage the boss grants you depends on the boss, as well as on the boss's level differential versus your civ level. If you kill a boss that is higher level than the civ level, you get substantially more exp (it's also much harder to do). When you kill a boss that is lower-level than you, the payoff is much less. If it's below about 5 levels, the amount becomes absolutely minuscule. So there's really no benefit to truly to grind low level bosses.
Putting up wind shelters, taking various macro-game actions, and so on also result in exp gain. A lot of those elements are newer implemented and still are going through some playtesting; world map movement and the fast travel system that I described in the past got majorly reworked as well thanks to playtesting, and the result is a lot more free and fun (and strategic) but also something we're having to re-test quite heavily for balance, etc. We're going to have a lot more to share in the next two weeks that I think our existing fans will be particularly excited about. All I can say for now, until we're sure everything fits the way we intend and is fun for sure.