The biggest problem I had with free to play games is that almost every one that I've played presents itself incomplete. There are very many things that you just absolutely need to purchase on a minimum level to play the game without feeling like you're being constricted and unable to breath at all times. For something like Mabinogi, it would be a bare minimum of one or two mounts, which already cover the cost of buying a game.
That follows constant reminders and nagging constrictions that always keep this "if only I had cash item X my life in this mmo would be so much easier" floating in the back of your head. When you're at the end of a 4 hour dungeon, and you've reduced the boss to 10% hp, and you die, you can't help but to think "30 cents for a ressurection stone won't hurt".
Usually, free to play games will give you the most ridiculously tiny inventory space possible. For anyone who sticks around with the game, your basic inventory space is always never enough. Once you've leveled up some, started crafting, etc, you realize that you need at least ten times that space to be able to play without crying over what loot to sacrifice in your farming trips. For mabinogi, people buy pets and service specifically to deal with this. For Vindictus, its recommended that the first nx item you buy is an inventory slot. And no matter how much you got, you still end up needing more and more.
I'll stop the examples here, but I can only go on for hours. The problem with these features are that they feel like something that should've been a part of the game from the beginning. Whats worse, is that a lot of these microtransaction features only stay active for a temporary time or for a limit number of uses (dyes for example, or inventory service), so to get what should've been a part of the game in the first place, you end up dishing out money for it repeatedly, almost as if you were playing a pay to play game.
What p2p services pretty much does is provide all of that bullshit for everyone equally. I didn't have to pay for a huge ass inventory. I didn't have to pay to get a fast as shit mount. I didn't have to pay to dye my clothes. It feels wonderful, even LIBERATING to not have a constant nagging subconscious "just buy it..." floating in the back of my mind.
It costs 40 dollars to make one set of avatars for one character in dungeon fighter online.
Control playerbase is something WoW does and look where it got them, people don't like to be controlled, as I was saying freedom or illusion of freedom will make people happy and subscription is the exact opposite of that.
I don't like WoW as much as the next guy but "where it got them" is an almost 12 year old game with 11 million concurrent users, boasting more sales and world wide players than any other pc game has never seen in all time.
Its a good thing subscriptions aren't working, or we'd have a real problem on our hands.