I was one of the first ever Wild geese in the experiments with them. I had no problem with switching sides, and in every server since have seen no problems with any who actually did switch. I agree that Wild Geese are not there to swing a server to a different outcome, but they do help fulfill the role of balancing out the teatertotter to a little closer to level. Never should it balance out the other way.
Becoming RM for a couple servers, I have not given in my name as a Goose, but still think they are needed. I know they are a bandaid, but to help stop a romp, a needed bandaid.
Should they switch daily or more? NO
Should they switch after a minimum say 3 days? If the numbers are clearly way off only.
Should they switch after 5 or more days? Sure, but only again if the numbers are clearly off.
The whole reasonning for having Wild Geese was to stop landslides, not change history.
As for trying to help out the losing side with extra metal, well, take that former example of 10 alliance vs 5 coalition. With only 5 coalition on, they cannot really take on any extra heavy metal as they do not have enough wings to fly with the metal they can already put on the map, with only 5 guys. Perhaps allowing some heavy metal to wing together under certain circumstances for a losing side would be better? Consider it this way, in war, your side is losing, you have only 5 platoons left. You still have 27 tanks, 4000 guns, 5 mortars, 17 planes, and other stuff. You would put your best combination together in a desperate attempt to either even the odds, or do the most damage you can in a losing cause.
So why not allow the side with a definite disadvantage the luxury of using say 2 heavy metals together? Of course we would need a couple rule conditions for this but I am confident it could be worked out.