IF and only IF the scripting AI for the NPCs is good will RT work well at all. I used RT in FOT a lot, but that system had some key weaknesses that need to be fixed, mostly in terms of NPC AI.
My basic problems with the RT in FOT (these would also apply to a real time FO RPG)
1. NPCs/AI-controlled anyone should pick their weapons/attacks better. Just because I left Brian holding his Rocket Launcher last time I touched him doesn't mean he should use it against a deathclaw already in melee with him. Likewise just because I left John holding his minigun, he might not ought use it in situations where friendly fire will be an issue. How much more AI would it take for these guys to manage to take the 2-3 steps before firing that would turn disaster into victory? And even outside such glaringly obvious situations, if I give you a tommy gun and a sniping rifle, and you can see a hostile too far away for your tommy gun, PULL THE RIFLE AND USE IT. FOT's AI wouldn't even use a weapon in the other slot if it was more appropriate (which is basically what I'm asking for here)
2. NPCs/AI-controlled anyone should use their frickin' heads about cover. If you are badly hurt and in the open, move to cover and bandage! Fallout systems to date have had badly wounded characters either remain fighting (and thus get killed) or else they pull out the stimpaks in the middle of the firefight, or even better, they'll sometimes try to run from a man with a gun, which would be ok if they moved for cover to block line-of-sight, but no, they literally try to outrun the bullets.
3. AI should assist each other. If Jumbo the Stupid is badly hurt and hiding behind cover, Roger the Medic should go help him. At the very least we should have a MUCH better interface than Fallout 2 for programming such behaviours.
4. When the AI runs out of ammo for the current weapon, it should use a different weapon if it has one. In FOT (and both Fallouts) the AI charged and started punching any time they ran outta bullets. Even if they have a loaded gun in their other slot!
5. Meaningful scripting of a Standard Operating Procedure for the group. I hate having to reload because a team member wasn't doing what I told him to, and thus we all got killed. Don't stop dead in your tracks cuz you see a mine, go around it if possible, or notify everyone of the minefield and call a general halt. Likewise when I tell Lenny the Bomb Tech to open something, he should use his frickin' head and check it for traps first. If I tell him to deal with a mine, he should go disarm it, not try to pick it up. The Formation command in FOT was totally worthless in this regard, formations were totally incapable of making 90-degree turns, and they didn't even stay in formation well in a straight line. Similarly I should be able to set my group to stop and engage hostiles on their way to somewhere I told them to move to. In FOT they'll just jog right past a hostile, getting shot, and won't even try to engage until they get to their destination.
6. Threat recognition. Though it is comical, I do get highly annoyed when NPCs decide that the cave rat over in the corner should be dispatched with extreme prejudice, so they pull their trusty rocket launcher. NPCs should evaluate threats and act accordingly. Against raiders and such, they should generally fire off a couple volleys before worrying about cover. Cave rats obviously don't call for the most powerful of all available weapons. Against Enclave troopers, perhaps it'd be best to seek cover FIRST, then worry about returning fire.
In short, if I can't directly control the NPCs, they better damn well behave in a manner befitting a semi-autonomous being, rather than one befitting a child. Sulik's predeliction for blasting friendlies with SMG fire is a great example here. Sulik certainly wasn't the brightest (or sanest) tool in the shed, but he wasn't a moron either. And Marcus was supposedly downright smart, but he'd do idiotic things with heavy weapons any chance he got. And even if we can directly control the NPCs, they better use their heads a bit. Better AI is key to real-time working at all. In Fallout 2, which was turn-based even, you had to very carefully set up your party, else they'd kill each other and probably you the first time they saw a cave rat. And in Fallout Tactics, the real-time mode illustrated clearly that the faults of bad AI are only magnified in real-time; at least when the AI does something mind-bogglingly stupid in turn-based, the survivors (if any) can all move out of the way before the NPC does it a second time. Real-time doesn't even give you that much.