Whatever you have been having with the 1er, it would seem that you had your time to decide to leave or not before deciding to join on the tournament.
If you leave the regiment you are playing in because of a heavy discussion or whatever is the reason, and then you claim that you still need practice, then perhaps what you should have done it's just to finish the tournament in the team you initially signed in. You could have had a good experience out of it even, and if you didn't think you feel like you don't belong there.
I have nothing against you joining the 4e, but I don't see being allowed to play for another team when you have been playing for 2 weeks it's the correct way to proceed.
And if you were to choose another regiment I would see it as bad, it's not the fact of joining any especific regiment.
My point on this new rule it's just something unnecesary that put it planly, no one apart from the people benefiting from it would see as normal.