When people talk about TB being too slow or RTwP being better for larger encounters you’re talking about RT without Pause. RTwP is designed to be played at the same pace as TB. If you want faster TB there’s no reason you can’t use the same scripts RT uses to speed up turns you don’t feel like controlling yourselves.
It depends on the TB approach. The major strength of RTwP is the simultaneous movement of opponents. Many TB games have the opponents not only move one by one, but the unit initiative makes player and AI turns mixed. So you get:
1) ToEE, Battle Brothers = individual unit turn order is based on initiative. This can get very slow and boring, especially in trash fights.
2) AoW = turn order is based on team, so all of your team moves in one turn. However, although there is a separate enemy turn during which you can do nothing but watch, all of his units still move one by one.
3) The Last Spell = turn order is based on team as in AoW. However, unlike in 2, movement is simultaneous for all enemy units. You might say that the player's turn is turn-based, but the enemy turn is real time.
I find that the last option is optimal, unless it is possible to turn off animation and make movement as well as AI calculation near-instant, which is rarely the case even in older games with better design like JA2. It would be particularly good for combat with many units. However, team-based turns might be said to be somewhat less tactically rich, although you need to do more prediction, which is good.
The big downside of RTwP is that may be tedious to manage if you have many units that do stupid stuff unless micromanaged. Say, in Paradox games, which are RTwP, it is a bother to follow 20 unit groups fighting in different parts of the world - that's in spite of the fact that combat is rather simple. But that is rarely an issue in RPGs, where units are few enough. There is the added advantage in RPGs that RTwP helps overcome perfectionism. Yeah, you're not using all the best moves and you're not squeezing out every last action point, you autist. You don't really have to micromanage that much in Baldur's Gate. The problem starts when the autism is so strong that you can't put up with the imperfections and begin optimising in an actiony fashion, like kiting enemies.
Civ4 has a pretty convenient semi real time system where it is your turn pretty much non-stop. However, it depends on you not abusing it when playing with the AI - in particular, no double turns by ending your turn and immediately moving before the AI can do anything.