I agree. Tablets are really useful, and there is clearly demand, but very little on offer in the quality tablet space.
There is Apple, there is the Samsung Galaxy Tab S, and there was the Sony Xperia Z Tablet series (now discontinued). The Kindle Fire HDX also has aspirations. Dell never played in the same league.
2-in-1 devices are certainly more flexible, but I find Windows really off-putting. It may be more powerful, but the App market is very sorry looking, and real Windows programs just do not scale properly for a tablet.