This is laughable. In the end, I'd rather have more options that increase a game's accessibility to more players (not to mention greatly enhance the game's replay value) than a few less bugs.
Not to mention that this "diversion of resources" was not "unnecessary", as the addition of turn-based mode will be of great benefit to the console port of the game. Real-Time is almost impossible to do well on a controller, as it necessitates extremely long pauses due to the incredible need for micromanagement in this type of game. No matter how good your control scheme is, this would make the game feel like a complete slog. Turn-based on the other hand never interrupts the flow of the game, and thus fits much better into the slower pace of gameplay that a controller creates.
This drastic increase in the appeal of the console port also has a secondary benefit in that many people who play RPGs prefer turn-based combat, which makes sense since the roots of these games are in a turn-based format and also since the gameplay in RPGs (but particularly in Pillars of Eternity) tends to have many layers of complexity. I'm very glad that more of the wider RPG community will care to experience the game, that turn-based mode will and has exposed Deadfire to a larger audience, as I'd greatly prefer forward-thinking, nuanced games like Deadfire to be leading the genre as opposed to games with shallow worldbuilding and storytelling (like Divinity Original Sin) or games overly obsessed with replicating tabletop mechanics in a format they weren't designed for (like Pathfinder Kingmaker).
Regardless, there's very little Obsidian can do to improve the gameplay of real-time combat in Deadfire without a complete overhaul. The few flaws that Deadfire's combat system has (like the Penetration System, for example) are fundamental, the kind of tweaking you can do post-launch can't account for fundamentally broken mechanics that literally every encounter in the game is built around. Even if the development of turn-based has turned away resources from adjusting the real-time gameplay, the fact that it operates differently also gives the developers working on that mode a lot more freedom, allowing them to get a lot more done with it then a focus on real-time ever would've carried. And besides, in the long-term, modders can probably more smartly handle such nuanced mechanical adjustments than the developers anyways. Like, there's already a penetration overhaul up on the Nexus last time I checked, and its really great. So if anything happens to fall through, the modding support this game allows for means that it can be addressed by the community anyways, so it is far more in the game and Obsidian's interest to expand on it's number of features and flexibility as a game.
Will turn-based ever be perfectly balanced? Probably not, but who cares? No game is ever perfectly balanced, as all things should be, but it doesn't mean it can't be very enjoyable regardless. I'd rather this community be larger and more influential than for Obsidian to be a few inches closer to a perfectly balanced game.
By the way, I think it's very strange to suggest that CRPGs as a genre are in fundamental conflict with a turn-based format, when they were initially built on top of a turn-based game: Dungeons & Dragons. Even POE, which greatly adjusted the format to function a lot better in real-time (which I would agree has caused some of the fundamental issues that TB mode currently has, like action speed), is still greatly influenced by that original material. So, if anything, the format is actually a great fit for these types of games as they get closer to replicating the core tabletop experience.