Ok....

This is not my personal favorite, but hey, its a tree therefore I like it. Cultivar Crimson King about 12' tall, 4' spread. Here's the deal. We bought our property 5 years ago and inherited this tree from the former owner. By the looks of it it was probably your typical Lowe's or Home Depot 6 foot generic subdivision tree sold in a container for $29.95. The area it was planted in is in a gravelly, sandy, rocky area with yes, some clay in it. (only spot in the yard). It is a very hot spot, full sun. It was ignored for 5 years and I admit it, I ignored it for 5 years too. And yes the leaves turn brown in the hot summer and well, its ugly. Well.. I got the tree bug 2 years ago and am determined to save it. I pulled out (yes pulled out by hand) its 10 year old neighbor Norway Crimson King 10' away to discover a fibrous 6" mass of rootlets, 12" depth coming out from the trunk (only on one side of the tree, the other half was bare!). To make matters worse, we are surrounded by beautiful sugar maples and across the yard, there is a Norway Crimson King that is gorgeous and about 4 times the size. A true lollipop. The Maple in question's leaves came out this spring in good form but there are several limbs with die back and the bark has split open a bit. Here's what I have done.... I have cleared back a 4' diameter of sod from the trunk (it had never been mulched, just stuck in the ground), watered the crap (slow drip with a hose) out of it, and have laid down a 4-5" mulch ring around it (being sure to keep 4" inches clear from the base of the trunk. I also peeled off the splitting (rotting) bark and treated it with the black pruning tar stuff. When I cleared the sod, I noticed several thin surface roots spreading out from the trunk but it seemed to have a fibrous mass around the trunk. Kind of like like it's neighbor I pulled out but admittedly much better. I did not notice any girdling roots. I suspect the tree is planted too deep. I found no root flare scraping with a trowel but didn't go too crazy. (it's neighbor I pulled out by hand was planted 8" too deep. What should I do? Keep digging to find the root flare, and when I do what then? Prune the fibrous root mass at the base of the trunk, "training" to grow outwards, be patient and wait a year or two and this is just a neglected tree and watering deeply once a week and TLC will prevail or .... cut it down and start new? Any advise would be appreciated.