Full range single drivers do have their following. That being said, it's incredibly difficult to engineer a single driver that will do a wide range (from low 50 Hz all the way up to high 20 kHz). Some can do this, but with compromises. I think the Mark Audio paper drivers are some of the most natural sounding full range, but they don't have good low bass response and the highs are soft and rolled off.
I've listened to several full range driver speakers and all have compromises. Either they are soft, or lack bass, or have whizzer cone artifacts. The Cube Audio Nenuphar look interesting with a 10" woofer and 3 whizzers. I have not heard them directly, but youtube videos seem to reveal the typical whizzer cone effect. It's a type of echo or resonance or shouty effect. It's not perfect and is not going to be as transparent or clean as a traditional tweeter, but it provides a single driver full range scenario.
The Seas Exotic 8 is another possibly decent full range solution.
I've listened to several full range driver speakers and all have compromises. Either they are soft, or lack bass, or have whizzer cone artifacts. The Cube Audio Nenuphar look interesting with a 10" woofer and 3 whizzers. I have not heard them directly, but youtube videos seem to reveal the typical whizzer cone effect. It's a type of echo or resonance or shouty effect. It's not perfect and is not going to be as transparent or clean as a traditional tweeter, but it provides a single driver full range scenario.
The Seas Exotic 8 is another possibly decent full range solution.