I'd like to be the lone dissenter here and voice my appreciation for Deadfire's turn-based mode.
Initially, upon hearing of the new turn-based mode, I was extremely sceptical. I figured it would make battles tedious, and slow down gameplay. I imagined all the ways the game wouldn't be balanced anymore. I assumed it would be half-baked.
Now those assumptions weren't entirely wrong.
The mode isn't entirely balanced. There are some abilities that are way stronger than they used to be. Dexterity is now a dump stat, for example.
Battles definitely require more patience, and it sometimes gets a little tedious waiting for enemies to take their turn.
Sometimes it feels like the mode hasn't been properly implemented. There are tooltips that don't show round durations, instead showing old durations, for example.
However, I feel like they aren't deal breakers:
Deadfire has never been balanced anyway. Resolve has always been a dump stat except for tanks, and even some tanks don't rely on it. So is one more dump stat suddenly going to make Deadfire significantly worse? I don't think so. It does mean that you can't rely on RTWP theorycrafting/guides. But I view this as a new challenge, something fun, rather than a negative. It's a new meta, if you like. Some are claiming that it 'ruins' Deadfire's mechanics, as if Deadfire's mechanics systems in RTWP are well-designed, and work really well together. They don't. There's very little to ruin, frankly. The entire system is a mess, whether you play it in RTWP or TB.
I personally haven't found the tedium too much to handle. And turn-based brings a new way of experiencing combat, one that allows individual actions and abilities to shine in a way that they just can't in RTWP. You experience each action in greater detail than you might if there were umpteen other things happening at the same time. However, I can't deny that occasionally, some battles are tedious, and on POTD sometimes it feels like you're attacking mountains of hitpoints. So it balances out, and ultimately I find myself preferring TB.
A lot of the issues seem to have been changed or fixed. I haven't played since 5.0 dropped, so I can't say for sure. But, hopefully, it feels a lot more like it's part of the core experience, rather than something tacked on, despite the aforementioned balance issues. That said, even prior to 5.0, when turn-based definitely felt tacked on, I still felt that it was an excellent addition to the game, and definitely worth experiencing.
Ultimately, I really think you should try out turn-based, and do so with an open mind. You'll probably go back to RTWP, just like the others in this thread, but there's a chance you might like it, that it might breathe new life in to the game.
Personally I feel that Deadfire's combat is dramatically improved by turn-based, and I'm glad that they implemented it, warts-and-all. And again, I say that as someone who was very sceptical about it, initially.