The article cited by OP is pure conjecture at best - and nothing new rumor-wise. I can't see WN nickel-and-diming customers with garbage fees, particularly as WN never has trouble raising fares since the other carriers are more than happy to follow suit.

Assigned seats are going to be controversial as both the advocates and detractors have passionate views. I don't think it will happen unless (1) Ops signs off, i.e. turnaround times are not affected, and (2) the result is at least revenue neutral.