So right now, you either have to use the bear Ultimate on both bars, or its gone when you switch... and seriously, that sucks. Yeah, its like that for most pets, but every other Pet that disapears when the skill is not slotted is a normal ability, not an ultimate.
How about this idea:
Wardens get an extra skill they get for free when they put the point in Feral Guardian, which can be slottet in the normal spell slots, and has no effect on its own, but when you have it in a bar without the bear ultimate and switch to that bar, you keep your bear unless you activate another Ultimate.
I think that would be a good change, because a) noone is forced to use it, so it doesnt affect players who dont care, giving up 20% of your second spell bar for a permanent bear seems like a fair price to pay, and while you can use a second Ult, it doesnt allow you to have 2 active ultimates, since the Bear is gone when you use your other ult.