And I still don't see why B-4 couldn't have been a mind-wiped Lore...
Off-hand I can think of two reasons:
1. How would you explain Lore's back-story to the audience who hadn't seen his episodes of TNG? I mean, trying to explain that he's the protoype for data who was deactivated 'cause he was kinda evil, then reactivated by the innocent Enterprise crew only to try and kill them, then jettisoned into space, then taken aboard a Pakled vessel and brought to Dr. Soongh's home world by way of homing device where he stole Data's emotion chip, after which he teamed up with a rogue band of Borg but was ultimately defeated after which Data got his chip back and Lore was deactivated. That's alot to explain.
2. If you could successfully explain the above, it would make the Enterprise crew look like a real bunch of boobs if they were willing to both activate him and dump a copy of Data's memory into him after all that. Well, a bigger bunch of boobs than they already were for finding a random android on a planet and doing that.
Yeah, I don't think you'd even need to "mind-wipe" Lore, and here's why:
1. He would require no more of a backstory than was necessary for the Borg (and Picard's alter-ego, Locutus) in
Star Trek: First Contact. Lore was an evil dog that had to be put down. How much more would the audience have needed? You don't even have to tell the film audience that the Enterprise-D crew was originally required to reassemble him in order for him to go apeshit. For all they know, he just showed up at some point. The general audience is given a half-assed yet reasonable explanation, while the fanbase is satisfied that their memories of how things really went haven't been completely trampled over.
2. In either case (both in the real
Star Trek: Nemesis and the hypothetical one), Data was the one who did the memory dump, not his crewmates. And, in this case, let's presume that the crew doesn't even have to go to the trouble of reassembling him. Shinzon and the Remans have already done so. Now you have true nemeses on two different fronts; Picard/Shinzon and Data/Lore. That having been said, Lore being implanted with the knowledge, memories and insight into humanity that Data has gained over the years would give his older brother the chance for redemption, something I think would have been cool to see.
The only problem I'd see with this is that Lore would make a much more formidable villain than Shinzon, and there's no way he'd ever play second fiddle to anybody unless he were the true evil pulling the strings behind the scenes. Suppose it's the Romulans, rather than the Remans, who pick Lore up and reassemble him in the hopes that they might use him against the Federation. HE'S the one that kills the Senate and helps Shinzon and the Remans position themselves into power.
Their next objective, similar to how it was in the movie, is to hunt down and kill their clones/brothers. Why? Shinzon has no freaking clue, but Lore sure as hell does, and Shinzon is unhinged enough from his time as a slave on Remus that any excuse Lore comes up with works for him. At some point, the Enterprise-E crew deactivates Lore and puts him in storage 'till they figure out just what to do with him, since disassembling him and leaving him on some random planet obviously didn't work. In the end, Data is forced to sacrifice himself to save everyone, but not before bestowing upon his brother the greatest gift he could give him.
In this way, it's not a TOTAL rip-off of
The Wrath of Khan. Data is most sincerely dead, but everything that made him who he was is inside the memory banks of Lore (you gotta figure those positronic brains have more than enough space for that amount of information), who now has a better appreciation for his brother and the universe in general.
Let me cite the reasons:
Can you make some for the other TNG movies (and TFF)? Then I can just link to your posts when people ask me how I feel about them. 
