I think that would have been cooler than introducing the Queen who IMHO ruined the Borg, though my dislike of the concept has more to do with how Voyager turned the character into a mustache twirling villain.
I feel having Locutus would have been a good replacement for the Queen as Picard’s rage in the film felt out of character. Picard had more or less come to terms with what happened to him during the series. He even managed to sympathize with individual Borgs like Hugh and his comrades. Having the symbol of his greatest failure and shame return would neatly explain his behavior. For this to work he would have to meet Locutus earlier during their attempt to puncture the plasma tank in act two. Having the crew also meet Locutus would cast more doubt in their minds to Picard’s mental state further strengthening his anger.
Locutus would also explain why the Borg would choose first contact, of all possible time periods, for their invasion. Picard is an avid amateur historian and archeologist. Locutus would have chosen that time because it’s important to Picard. There’s already a scene in the film where Picard, with Data, touches Cochran’s rocket and talks about his admiration for the ship
Speaking of Data, the attempt to convert him would have felt more believable with Locutus. I thought the queen trying to seduce him was kinda silly. Data’s respect for Picard would have been something Locutus could exploit.
The return of Locutus could easily be explained with a clone body and Picard’s mind being copied to the collective while he was a borg. Having cloning in First Contact could also have meant they wouldn’t have used that plot point again and sparing us all from the turd that was Nemesis.
The problem in Nemesis it was the bad script and directing and not the cloning. Locutus being a clone would be a minor plot point anyways. The main thing would be that Picard’s mind is still a part of the collective. Having Locutus return in a clone of Picard would just have meant that the film would have had double the Patrick Stewart, which in my mind isn’t a bad thing.
Clone? why think in “such three-dimensional terms”? This is a TIME TRAVEL story. Picard said the Borg Queen was destroyed at Wolf 359. She was destoryed again in ST:FC. She still showed up in Voyager. No reason that this Locutus couldn’t have been a time-displaced version of the original.
But with that said, I kinda liked the queen, before VOY screwed her (and everything else) up.
I like the queen, but I don’t think she is in charge (or existed before First Contact). The queen is yet another Borg “adaptation”. Since the Borg suffered what was likely a major (possibly unprecedented) defeat in Best of Both Worlds, the Borg “adapted” by creating a (single layer) hierarchical command structure. She is the embodiment of the “we will adapt your distinctiveness”; in this case, non-collective thinking. She represents the blend of collective and individuality.
Plus. she’s a trap for Picard - he might think of her as a person that can be reasoned with.
Still, I like the idea in the OP. Might have made a better film. That, and leaving out the Moby Dick-ishness.
The thing about every appearance of the Borg is that there’s always an element that contradicts an earlier appearance of the Borg. I think it was a contractual obligation or something.