Iresso > Qyzen in every way shape and form. I don't even truly like Iresso since he's a ranged tank and doesn't always jump into the fray, but he's better than the oversized lizard.
The only workaround for this is to expand Iresso's bar and pull with Ctrl+9 instead of Ctrl+1, and he'll charge into melee every time (since you're specifically calling out his rifle butt charge).
I filed a bug report on being unable to use pet hotkeys after the first four if the pet's bar isn't expanded, stupid oversight.
I suggest everyone else interested in seeing it fixed do so as well.