In the near future, I think markers will be made of dreams and powered by love. And they'll shoot sexually explicit language instead of paintballs. And they'll all be splash anodised.
The goggle HUD system sounds awesome maby expensive but possible if you think about it Also having some kind of radio mic in there to talk to team mates would save you shouting to them
Similar to what the American Football players have in The 6th Day would be ace
In all fairness I see the whole thing coming down to a race to pataint new ideas and eventually 1 or 2 companies will get such a hold in this area it kills off the other competition.
Imagine a Halo backplate being a screen giving you a game timer, RoF counter, balls remaining in the hopper, Dwell, Fire modes. perhaps even linking to your other players to report how many players you still have live on the field?