I think I'd rather deal with some cracking/sinking pavers now and then than to have to deal with potentially worse repercussions for doing the job "right." It seems to me the proper way to do a paver patio is only for certain property layouts and certain patio locations. My property was designed to direct rain runoff right past my back door, and the proposed paver patio would be in the flow's path. It's not going to get a lot of traffic... only light foot traffic, so I know that matters, too. I am wondering now, though, if excavation won't be a problem so long as I don't go lower than the excavated level of the existing concrete patio. That would give me at least a bit of depth to work with. Still, in the deep South, I have to wonder how much is truly necessary. It's not like it's going to heave with deep freezes every winter. [SHRUG]

You bring up another concern I had, which was the sand washing out of the installation. I am not even sure how this isn't a given and something to be expected. I read that pavers can be installed on an existing concrete patio, something I was interested in doing to have the old and new areas match, but I was concerned because the recommendation was to put a layer of sand on the concrete patio. I immediately thought about the sand washing away over time.

Hire an established and experienced landscape contractor with sufficient masonry skills that is local to your area. They will know the best way to address this. Setting the pavers with an appropriate depth of base material really has little to do with freeze/thaw issues but has everything to do with the stability of the patio being constructed. No freeze/thaw issues in my area either but this is SOP for any paver patio installation. While I would agree that a modestly sized paver patio is a reasonable DIY project, the concerns you have concerning run-off and drainage elevate this to a different level.

The only time sand should be washing out of the installation is if a) no rigid edging was used to confine the base material or b) it is being power washed to clean and the sand is being blasted out of the joints. Using polymeric sand on thin or narrow joints is a way to avoid that (or avoid the power washer to clean) but obviously a 4" joint is far too wide to use sand.

Your proposed idea of planting dwarf mondo between pavers is perfect ... for making a patio unusable! Stuff some socks to make them like pillows and then lay them out in grid fashion in your living room and see if that makes the living room floor easier to use. I think it will make walking and arranging furniture harder.

Does the grade work now for proper drainage? Then a patio surface would correspond accordingly to make its finished grade work properly. I'm sure it can be done without any issues. Sand washing out of a patio is only a problem when something is not built right. The patio could be flush with grade, so that it is entirely surrounded by a hidden paver restraint and earth which prevent sand from washing out. Or, if a patio is raised, it has some type of solid curb-like edge which contains all the sand and keeps it from washing out. It is not a problem.

It's much more likely that people could help you with your specific problems if you show a picture of the area and surroundings where a patio might go. Line up the camera square on and central to the subject matter. To show grade, photograph across the grade, not in line with it. Both of these objectives would likely require pictures from two different camera positions.

Keep your drainage flowing. A contractor will do it to make money. If you want an expert get an engineer but the water needs to runoff, not be dammed up. I tried the dwarf Mondo grass between pavers and in the summer heat of Texas with pavers only absorbing heat, it was a loosing battle to keep it alive.

Memetexas that's definitely something to consider. I had thought about just doing a trial area of the mondo to see how it takes and maintains because I'm open to using gravel between pavers, too. Even better point about the engineer.