Looks beefy, but with caveats:
1. The memory. Not only it's weird split between 10GB and 6GB, but also the fact that it's only 16 GB total. Most modern high-end PCs are already at 32GB, and they don't need to share that with the GPU. And as the RX 5600 shows, 6GB VRAM are already starting to become a limiting factor in 1440p, so the amount of RAM left for the CPU is pretty small right off the start. Microsoft tried to soften the blow with virtual memory from the SSD, but even the fastest SSD can't keep up with DRAM chips and the whole program will become noticeable slower when it has to draw from virtual memory at any point.
2. proprietary SSD. That external SSD extension will certainly not be cheap, remember those from the 360 or the Vita? And considering the size AAA games will have next gen, 1 TB will fill up very fast.
3. The price. Certainly won't be cheap, $499 is really the floor, and that's sold at a loss.