RTwP results in me not even adding anyone else to the party.
Why? RTwP makes it possible to effectively manage a full party
(1) AI fucks it up. For example, I was playing DAI the other day, soloing on the highest difficulty. I do have two companions (one warrior, one mage - I'm playing a rogue), but I never applied any skill points or gear and have their AI turned off (I have them trail me to open doors when needed; they die very quickly in combat, if not right away, and never attack). A minute or two into the battle, rolling along without any real danger, I accidentally switched to one of the companions in combat, which then made my character operate by AI (this companion usually survives in combat because of a ring that turns her invisible at the start of combat, and since she doesn't attack, she just stands there doing nothing and not getting attacked). It took a couple of seconds before I realized and reacted to regain control. In those two seconds of having the AI in control, my character almost died, because "AI" is anything but "Intelligent." One way or another, AI finds a way to do something stupid, be it cause a train, squander a potion or scroll, or any number of things.
(2) RTwP feels like a bad hybrid. RT and TB are both standard methods that work well for what they are, but having to rely on the "P" makes RTwP feel neither here nor there. In fact, it shouldn't even be called RTwP, because real time doesn't stop. Call it what it is, STwP (Simultaneous Turns with Pause), or maybe even HART or HATB (half-assed real-time or half-assed turn-based). Yeah, I know, plenty of people like it, and that's cool. I don't. It's an attempt to get the best of both worlds and, as usual, ends up getting the best of neither.