Yeah, I can imagine there can be different ways of implementing asteroids like that; from temporarily damaging movement or weapon systems to taking out the shield/destroying a ship. It just makes them something to pay a little more attention to, because at the moment they only throw up a small barrier or push you away a little.
I'm also not that much pro-powerups, but was just trying to think along with fellow players. I can definitely see why it's not something that fits with the current direction of the game. The way your shield regeneration works also severely limits the impact of said powerups. I prefer a more tactile approach to the matches like it must be atm (still need to get around to trying local mp, grrr).