How about a weapon which instead of knock back does knock forward? the missile fires over the enemy, landing behind to create a forward blast effect.

How about indication of how many players which are online are actually searching for or in multiplayer matches? For example, adding a second line to the display graph of players. Particularly useful at higher levels where (I believe) its harder to get a match. No point searching if the other players are vs computer.

How about an (toggle on/off) option to automatically search for a pvp opponent at the end of each vs computer match before going onto the next computer match?

EDIT to add
I forgot this one - a store option to buy a premium account for a shorter period of time, at an increased per-day cost of course. I was thinking of a week pass and a weekend pass.
I'd price a week pass at about 1/3 of a month pass, and a weekend pass at about 1/4 - so paying for each weekend in a month costs the same as paying for a month.
This would work for some people who find the monthly amount expensive, and would be a great option for a school holiday - or parents who want to occupy the kids for a week break from school

I have been thinking about weapons that could knock players forward ( like a giant magnet or tractor beam). But, it would make trying to walk/drive away from a player a little bit more difficult though.

Anyways, I could see this being used to get players out from the edges of the map or used to set up different combinations of attacks. Of course, It would have to depend on the range of the weapon and how much it can Knock a player forward.