I would really rather the core game was right, considering it may well be built on for future releases (DLCs, spinoffs, sequels). We shouldn’t need mods for all of those too. Besides, the more Larian improvise, the more work they’re making for themselves trying to balance things later on (assuming they care about balance). I wish they would trust the rules. Flaming Sphere is just the latest example of how they’re trying to shoehorn D&D into their mechanics rather than build systems to make it work that will useful for other spells. I think we can extrapolate that Spiritual Weapon is going to be just as mangled.
Going so far off-piste is really going to hurt if Larian does end up pursuing a DM mode. Having a really strong foundation that could be used for people to build modules and run games like a VTT would be incredible, especially for folks who can’t play D&D in the same room. But that won’t work if the ruleset is some kind of bastardised offshoot that will only get more hackneyed as more subclasses, spells etc are added in from other sourcebooks.
Perhaps I’m better off placing my hope in the Solasta team, maybe if the game does well enough they’ll have the resources to work in that direction.
I'm starting to suspect that the engine Larian is using just can't support the ability to use a player action to move a spell effect, which is why all summons are their own separate controllable entity. The engine also doesn't support true flight, which is why you have Harpies jumping everywhere, Flaming Sphere rolls on the ground, and so on and so forth. It would not be too much of a stretch to believe that Spiritual Weapon would work in exactly the same way. (Coincidentally, there is no example of true flight in D:OS2 either, there was a spell that allowed you to sprout wings in that game, but all it did was to give you the ability to spend an extra point of AP to jump huge distances for about 3 turns.)
I wish Larian would just go out and say it if my suspicions are correct. It would do wonders in managing expectations around here, and direct suggestions towards things that are actually possible to begin with. (And if they make a sequel, please for the love of all that's holy, build a new engine from scratch. The BG series does not deserve to be tied to a game engine that originated from an entirely different series, and I say this as someone that has never played BG1 and BG2)