Floaters CAN NOT be used outside of the Risa Summer Event map nor will they become usable outside of the Risa Summer Event.
The maps have to be specially tailored for the floaters. The invisible walls that limit player movements in older maps where only designed for the height that a player can jump. Every map would have to be completely modified before they could decide to allow floaters on them.
What Cryptic could do is create more maps specially designed for floater usage at a later date, however there has been no indication that they have any current plans to do so.
Personally I'd love to see the floaters being combined with the EVA suites and having that combination being useable for some space EVA missions.