A recent Reddit thread was talking about the future of MMOs, and this is something I feel is central to the future of the genre. Right now, it seems like MMOs are primarily divided into two camps: subscription-based ("pay to play") and free-to-play ("pay to win"). Neither system is really ideal.
Subscription-based models ensure a steady flow of revenue for the developer and are thus very developer-friendly, but also require the player to pay the same fee each and every month, regardless of how much fun they're having, or how much they play, making it a fairly consumer-unfriendly model. Generally speaking, these games are primarily focused on PvE/raiding, and the turnaround time for each major content push seems to be around 90-120 days, with the "standard" fee usually being $15 a month. The major downside of this business model is that, even if you only play a couple hours a week, you're still paying the same amount of money as someone that plays 40 or more hours a week. And as a result of these differences between players, the developer often feels the need to put a lot of grinds into the content to try and ensure players continue paying that fee for all three to four months between each major content push: these games often see a surge of fees when new content patches are released, with fees often ebbing between surges.
Free to play models are generally pretty consumer-friendly, since you can technically play the game completely for free (which also makes them somewhat risky for the developer, especially since the developer has to provide bandwidth and storage for all of their players), but these games often feature excessive grinding or outright "give me money to get a huge advantage over other players" mechanics featured around their cash currency and microtransactions. Depending on the developer, these games may also be focused on PvE/raiding, or they may not have an "endgame" at all, especially if they're shovelware. The danger of this business model is alienating players who don't wish to pay for everything; if someone spends 40 hours grinding for a piece of equipment that someone could spend 3 hours getting by buying some of the components (or XP/token boosters) from the cash shop, you run the risk of completely alienating those players. And, true, those players aren't giving you as much money as the 3 hour players are, but you're still losing a potential source of revenue - just because a player doesn't want to spend $10 to get an item faster doesn't mean they'd be uninterested in buying cosmetic items or other things of that nature.
So where can the industry go? Some companies, like Guild Wars 2's ArenaNet, have sort of split the difference; GW2 has an upfront box cost (usually $50, but it will frequently go on sale for $30 or less), but once that's paid, it's completely free to play, and there's a relative lack of grinding throughout. ArenaNet also has a cash shop and cash currency where you can buy a wide variety of boosters, cosmetic items, and things like additional inventory, bank, or character slots. And it seems to be working quite well for them.
And while I really like that business model, it's hardly the only one possible.
Why not make subscription models broken up into segments? $5 for open world, $5 for access to ranked PvP, $5 for access to raiding content? I'd be glad to pay $5 a month for just the open world/questing content in WoW or FF14, and if I decided I had a desire to raid or do some PvP... well, I can easily add that my subscription!
Or why not do something akin to the old Guild Wars model, where there's no subscription fee, and you instead release small expansions pretty regularly, at reasonable prices? Imagine if WoW had no subscription fee, but instead you had to pay a one-time $20 fee if you wanted to access that new patch's raid content, the new PvP season, new quests and zones, and things like that?