Since the devs are so busy elsewhere, it may turn into a joint effort like autobalance/score that will take months to get to a nice spot if something is done.
I personally think the multi system is too heavily weighted on winning consecutive times. I don't think that's really effective as a rewarding device, and it runs counter to a good functioning autobalance. I think one should be rewarded more for sustained good play for the entire map that provides better rewards for lower levels. Valour rewards extraordinary performance for a single round.
Some form of multi rewards getting your team to win. However, there really isn't anything for simply doing your work as a valuable member of the team. In an appropriately packed server, the multi is not much different than a coin flip for the average player. Siege definitely needs its own tweaked system as well, since guarding locations can be just as important as fighting at the front lines.