Commenter Alucian states:
unlike other MMOs, Blizzard actually scales xp needed to level and gained from quests with the current number of levels to max. They ensure it takes the same amount of time to get from 1-endgame whatever the max level may be.
This is an interesting notion to me, one I have not considered because I have been through only one level cap increase (CoX does not count) in my ten MMO years (old old old). Every time you increase the level cap, you can change the rate of experience accumulation so that time to cap is unchanged.
Would you wait a few months after the new expansion to do so? On one hand, you don’t want existing players to feel like their “work” has been “cheapened.” On the other hand, the expansion will not be terribly helpful in recruiting new players if they see months between them and that shiny new expansion. There is also the scaling o, that. Many games seem to want the last ten levels to take as long as all the levels before them, or the expansion to take as long as the old “late levels.” You would need to halve the old late levels’ leveling time to make the new time-to-cap fit, with the new late levels taking as long as the old late levels did.
If you keep re-scaling experience, and your level cap keeps rising, you eventually will have players leveling by walking near the newbie zones. Alternately, your time to level through later expansions would be increasingly short, although that might not be an entirely bad thing. If you do not keep re-scaling experience, you start seeing a dizzying distance from level 1 to the cap, particularly if you obey that principle of how long the last 10 levels should take. You could keep that time constant, so 1-40 takes 120 hours, 40-50 takes 120 hours, 50-60 takes 120 hours, etc. I think it would quickly become insane with the “50-60 takes 240 hours, 60-70 takes 480 hours…” interpretation.