According to producer letter X, surplus will be removed "following balance adjustments". This clearly suggests that they consider straight-up removing surplus a bad move as it would allow "hardcore" players to level much faster. That means they're most likely going to nerf grinding SP across the board when they do it while further incentivizing strictly limited progress methods (the announced leve/quest completion rewards).
This is entirely speculative of course, but I have a hard time reading "balance adjustments" any other way.