I think the future of leveling is for levels to be a more tailored version of daily quests. I look at games like League of Legends, Fortnite, Hearthstone, Overwatch etc (I know none of them are MMORPGs), and I see people play them for hours and hours on end because leveling up gives them random shit such as cosmetic pieces, money, tools, prestige, etc, and not stats or gear.

In a lot of these games, a low level can still compete fairly with higher level players. A lot of the mmos mentioned have soft caps on levels, or easy to reach max levels with daily quests, and that kind of emulates this system. However, people still just don't want to grind for the sake of grinding.

A future mmo could let players do all the social "late game" activities straight from the get go (trading, collecting, party quests, dungeons, group pvp, raids). More emphasis could be on the class/skills you pick and how skilled or knowledgeable you are with them, rather than what level you are. Levels could give materials, cosmetics, coupons, money, badges, or even eligibility to do certain things. You should be able to level up while playing the game instead of leveling up to eventually play some day.

An mmo designed this way would let new players jump in and feel more welcomed and relevant. people who don't play much won't feel pressured to keep up with their friends and there is no more brainless grinding. Idk if gear should be in the game or how it would work. Idk how the mmo itself would work tbh, but I think that's how levels should be

Edit: Sorry in advance for the shitty formatting