I just got into a full alliance match with a single party. One. Party. Needless to say we lost.
1) Matches should replenish members while inside the starting gate.
2) Matches should not be able to start until each alliance at least has the same number of parties.
2a) Or, an echo-like buff scaled to the number of missing people should be applied to the team(s) down members that decreases as more people entered in order to balance the discrepency.