I think Morrowind, NWN and combat systems like this have more potential than a straight real-time action combat system. But Morrowind shows that a lot of people don't like abstractive combat. "I'm swinging and it looks like my sword is hitting the enemy but they aren't taking damage! This sucks!" But really it was just a heavily abstracted combat system that wasn't all that different from Baldur's Gate or any RPG that is dice and stat-based, i.e. pen-and-paper style mechanics. The "problem" was that the first-person view combined with the pnp mechanics confused people.
Skyrim has a good real-time combat system, IMO. You can pause the game and bring up the quick menu with a button press, so it's sort of like RTWP in a way. It's intense at times, running around trying to fight a dragon while it's flying and breathing fire, blocking attacks and activating Perks that change the combat. For a first-person system that they still want to try and sell a lot of copies, it's probably the best we've got. I went back recently and watched my dad play the game a bit, and there are quite a few options in the game of how to change combat, develop your character and do different neat things in combat (blocking arrows or elemental magic, sprint attacks, slowing down time while you aim an arrow and much more.)
If I were designing an RPG it would be a Morrowind + NWN hybrid combat system. Morrowind-style exploration, first-person view, but NWN/Baldur's Gate "rounds" in combat, RTWP and combat encounters that require tactics and are balanced to be a bit longer than the current Morrowind encounters (they are very short and over before you can really use the tactics you have at your disposal.) Make a mixture of the Morrowind and D&D 3.5 ruleset, add a ton of stuff from the two magic systems so you get a lot of creativity in the spell system, keep Spellmaking and Enchanting, and you'd have a pretty insanely creative and fun "playground" to develop your character. It would confuse people, no doubt, and would be a niche title probably, but I think it could be interesting.
So who wants to help me make the game?! I can design it, but I would need someone with talent for doing the hard work of making it while I just shout orders and tell you what to do. Any takers?