As Tobold writes, the pace of leveling is much less important than whether players enjoy doing whatever it is they are asked to do as they level. Many of the current problems in the genre are caused by developers' continued insistence of using the primarily solo leveling game as a prerequisite for group-based endgame activities. This turns a segment of the game that is the entire experience for many customers into a menial grind that stands between other customers and actually playing the game with their friends.
Even so, developers have financial incentives that are influenced by how they set their advancement curve, and I would argue that the consequences of getting the curve wrong vary based on the business model. Regardless of business model, no developer wants advancement to be too fast, as every model out there ultimately makes more money if players stick with the game. On the opposite extreme, however, the incentives are very different.
- In a subscription game where any added transactions do not affect the rate of advancement, the goal is to satisfy as many of the customers as possible. As Tobold says, this is an impossible task, but the developer will have to strike some sort of balance between losing income from players who get to cap too quickly versus being branded overly grindy. For many players, merely describing the slower rates of advancement often observed in games developed for the Asian market is the beginning and the end of their interest in the game.
- In a subscription game that also offers faster advancement, however, that loss of income begins to be offset by sales of experience potions and other means of accelerated progression.
- At the furthest extreme, a model where there is no recurring subscription, only sales of theoretically optional stuff like exp potions, there is very little marginal loss of income due to being thought of as "too grindy" because 90% of players aren't paying a dime to begin with. Yes, you might drive off some players who might have otherwise have bought mounts and costumes, but your primary demographic is the market that will pay to have exp boosts up and running as close to full time as possible. In other words, your lost income if a big spender decides they don't need to buy potions because the curve isn't grindy enough is much greater than your lost income from driving off significant numbers of less dedicated players with a grind.
This does not mean that every game that sells some form of exp boost is doomed to be a grindfest. In fact, I'd argue that selling max level characters might actually improve the leveling game for those who want to play it. However, as I noted a bit ago, the direction of a game developed by a for profit entity is never completely separate from how they make their money.