bad when you have to take 10 minutes beating a trivial fight, because of how long turns take.
Arcanum did it right
As much as this is probably a joke post, there's some truth to this.
Arcanum's combat isn't that great but it's serviceable. Full companion control would even make its turn based combat into a genuinely good combat
system (emphasis on system because the encounter design of Arcanum is, with few exceptions, utterly abysmal). It gives you plenty of tactical choice and different skills and abilities to play around with. Go for a mage, or use grenades as a techie, or go for fast bows or melee, lots of options there. Arcanum's TB combat with proper party control and some bugfixing would be genuinely great.
And for the trivial encounters against low-level enemies, like when you go to a wolf cave at level 50 and know you'll just roflstomp everything? Switch to real time combat and have it be over within 5 seconds. Arcanum's RT combat is over so quickly, trash mob encounters become a non-issue.
If the TB combat system is properly developed, adding in a fast-as-hell RT combat system as an option like Arcanum did would be a really, really good thing. It doesn't even need to be balanced to be at the same level as the TB system. Just make it a quick thing like Arcanum did, and if the casuals go for the "story-focused" difficulty setting that makes combat trivial anyway, this fast RT system means they won't even have to waste any time with trivial encounters. In RT mode, no encounter in Arcanum takes more than half a minute.
Alternatively, go for what Troika did in ToEE. Make enemies that have their turn right next to each other move as one, playing their animations simultaneously. 6 orc fighters having their turn right in sequence? Boom, they all move as one mob, you won't have to sit there and wait for 6 orcs walking seperately, one after the other.
As mediocre as Troika's encounter design was (ToEE had some really good encounters, but most of them were meh), they knew how to implement systems that remove the lame aspects of turn-based combat completely (which is, the aspect of slowly waiting for the enemy turns to pass).