I don't know, in MMOs I feel like F2P models have only been implemented once the game was recognized as a failure by the public and the developer.
I cannot think at the top of my head of an MMO that released as F2P and can be considered a success, yes some (terrible) P2P games did have more success when they moved to F2P but that is precisely due to the fact that no sane person would pay money monthly to play a bad game, while a free "bad" game can still be a fun pass time (and you can play only the good parts while ignoring all the crappy parts in a free mmo take SWOTOR I only play it for putball pvp).
I guess that the difference between MMO F2P and Moba F2P (which is why you can't compare the two) is purely based on the content expected by the players. In an MMO people cannot be satisfied by purely cosmetic gear and cutsy fun events, they require a sense of achievement tied to that piece of "cosmetic gear" as they are creating that character from scratch. Take the new trasmog helmets in WoW, I have the money to buy them, but will I? ABSOLUTELY NO! because even if they look cool they do not satisfy me in any way shape or form, just like any purchasable mount or pet, I did not achieve it I BOUGHT it, and in an MMORPG player's mind that is pretty much unacceptable (just imagine cheating in skyrim to get your full set of dragon armor just to look cool). I prefer a million times to farm Molten core for my badass T1 warlock set than to buy a helmet skin because that is what MMORPGs are about, developing a character from scratch by PLAYING the game.
What about XP boosts, Rep boosts and all that other junk? well they are also terribly unballanced and do not belong in a MMORPG, and I do not care what other people say, to me that is pay to win, the moment in which by paying 5$ you get to reach a level faster or reach exalted with a faction faster you are effectively enhancing your chance to gear up your character (which again is the point of a MMORPG). These boosts can only work in a ballanced way once the game has been out for a while and there is no more competition in achieving Tier 1 raiding gear, racing to level cap, or racing to reputation caps, but on release they are absolutely unacceptable.
What about character slots, bags, and other commodities, well I have less issues with them, however, I still think that they ruin the initial progression of the game. For example on release a guy with 20$ to throw will be able to level professions faster with larger bag slots. (character slots are fine at any point).
Unlike an MMO, a Moba is based on premade CHAMPIONS, this means that you have no real sense of achievement tied to the cosmetic / performance aspect of the champion. Other than particular skins (such as triumphant Ryze in LoL) 99.9% of skins have absolutely no other purpose than making you like that particular champion more. I'd say that what you buy in MMORPG f2p games would be more like if in a MOBA you could buy ladder points (in other words removing the purpose of why you are playing, trading in money in order to put less effort in the game).
In conclusion what I'm trying to say is that the F2P model in MMOs only truly works in a ballanced and effective way after the game and its player base has consolidated and the game no longer has a "hardcore" competitive aspect (rushing to cap, competitive pve/pvp). In mobas this isn't a problem because in the cash shops money does not replace effort, which is precisely what money cash shops remove in MMORPGs effort.
Sorry for the long rant, but I wanted to put my 2 cents in the discussion.
PS: long live the subscription model!