Jellico was a dick.
But, he was a dick who was also in command of the Enterprise.
Jellico was right, and Riker was not. Yes, Riker dressed him down off the record quite well. But he was still wrong for not following orders and implementing Jellico's directives.
I think an XO who won't let the crew be pushed beyond their limits is better than an XO who will just blindly follow the captain's orders.