Though unlikely to see anytime soon, I'd be happy to see some sort of soaker-storage system that consists of something a little more pleasing and soaker-friendly than closet space, large plastic bins, or shelving. Granted, due to the wide variety of shapes and forms soakers have, making a universal-type soaker rack would be pretty tricky.
Better filling systems would be good. Many use hoses or fawcets to fill, but due to blaster reservoir openings and water pressure, this can lead to slow and messy refill times. Some sort of universal soaker filler with an auto-shut-off device similar to that used by gas-pump nozzles would be nice. Add on a system for filling soakers more easily from a basin of water via a simple pump and this opens up water warfare in more places where perhaps only buckets of water as opposed to hoses are available. Sure you can pour from a bucket into a soaker,but a controlled pump is cleaner and less wasteful (and even potentially faster). If it were cheap enough (~$10-$15 dollars) and simple to use, I'd even say pump-filling a soaker may be preferred over a hose since one could set up multiple filling stations around a single hose with enough buckets as opposed to having one person fill at a time.
Team ID tags... something cheap, simple, and waterproof, but easily seen. Granted, there are things out there that can be used (i.e. bits of coloured rope or cloth, etc), but sometimes not as easily found.
Target practice set for soakers. At some amusement parks, I've used motorized water cannons to fire at various targets and shapes to score points. Why not have some stationary targets for soaker games. I could imagine having the target's size be similar to a body target so players can practice their aim prior to actual battle or players using a series of targets to hone their skills when running some sort of obstacle course.
These are just some thoughts...
