Depends on the players that show up when/if it goes f2p completely. One of the reasons I really hoped that Zenimax would go with a sub was the "players" I ran into on other f2p games. Not exactly the most story oriented, invested in the game type of player. Mostly the kind of player that made me quit, actually. Which was easy, because there was nothing there to attempt to keep my interest/loyalty. It was free, what did I care? Needing to buy keys, better weapons, armor, mount, whatever, with real money didn't help.
If the content is there, and I'm invested in the game, *and* I have a sub, I'm far more likely to stay. The fact that I can buy a name change, or someone else can buy rainbow stripes for their horse if they want isn't the same to me and doesn't bother me. It isn't the same as wanting/needing to buy keys to open loot or upper tier weapons and armor that otherwise you'd spend days grinding to get, if you were extremely lucky.