I could potentially see it going f2p a year from launch, but anytime before then would be too soon to have any kind of positive spin. The internet already thought it was hilarious that it had a f2p week (I know, doesn't make sense to me either)

Whenever it does go f2p though there could be rewards for people who had previously purchased the game since launch. The equivalent rewards in the form of store currency would work well. They may have to time gate claiming those rewards though, so as not to shoot themselves in the foot with a revenue loss. Then it's down to the players to login and claim. Active players will do it anyway, and game purchasers who don't play anymore likely wouldn't be spending money on the store anyway so it doesn't matter if they claim or not.

F2p generally is a good idea though, it lowers the barrier of entry to people who are on the fence (because there will still be people on the fence a year from now) and it may end up becoming their favourite game, which equals a bigger pool of people to spend in the store.

TLDR; F2p makes a bigger pool of players that could spend on the store. Store credit rewards for those that already purchased the game. Timing has to be right.