Now, don't quote me on this, but I'm fairly sure that all ride tech suspension kits lower the vehicle ride height 1-2inches by design. If set up right and paired with a good set of shocks, air ride can be very smooth. I can't comment on the standard shocks that come with Ride Tech kits as I have always used different shocks. I went with the shock waves on the front so I didn't loose turning radius because of the shock relocation with the cool ride system. Yes I would say that having an on board air system is something that should be installed, tho you don't need anything too fancy, just something to keep air in the bags in case you develop a leak while your out on the road.
But I agree with the others you should be able to achieve a nice ride with good shocks and stock springs. The advantages off the air ride in my mind is adjustability, more load capacity and performance with out sacrificing ride quality.
If you do decide you want to go with air ride I'd be happy to help out with ways to plum up a cheap air system that will do the job for much less then the kits Ridtech sells. Just send me a PM