You do need a WDH, but the factory brake controller will be fine.
I pull a 25' 5,500 lb camper using the factory controller on my rig, and it works just fine, no issues at all.
And as far as air bags, if you're gonna go that route, may as well do it right the 1st time and get the TLC system.
I've personally found in the long run, spending the extra up front is a lot cheaper and a lot less hassle then buying cheaper, then having to replace it later on cuz it don't work anymore or isn't enough anymore.
1996 Cherokee Sport 4x4
1988 Cherokee Pioneer 4x4