The problem is that the crates aren't getting equal 3 month seasons. And instead of just extending Reaper's out until January, they're keeping December as a firm beginning of the seasonal year.
I think that's a bigger issue than the crates themselves. If you want a random system to feel fair, each season needs to have almost exactly the same number of days. Two more or two fewer days won't be a big deal. Cutting nearly a month off one is.
Expectation:
Storm Atronach: December, January, February
Wild Hunt: March, April, May
Dwemer: June, July, August
Reaper's: September, October, November
Reality:
Storm Atronach: December, January, February
Wild Hunt: March, April, May, June
Dwemer: July, August, September
Reaper's: October, November