I appreciate the effort of the original post and I fully agree there are (rather simple) solutions to the problem, especially doing things like some item transfer but not everything.
That said, you're making a fatal mistake in looking for solutions: LG doesn't want solutions.
This is 100% due to marketing. I already outlined the explanation here: New database
The TLDR; is if there are already players who have stuff at launch, a certain group of day 1 mega whales who like to race for the top spot won't even bother because they'll first have to whale to catch-up. They don't want to play catch-up first, they want their money to immediately put them ahead, so they'll just wait for a different game with a true fresh launch to jump on instead.
That's all this is about; making whales compete so LG can maximize profit at launch.
Everything else is a lie or half-truth.
After what LG wrote on their Facebook page, I'm fairly certain that they are the ones who decided not to transfer the user data. I don't think that trying to convince Gameforge of a data transfer will result in anything. LG are the ones blocking them and what should Gameforge's interest be to convince LG otherwise? There is no incentive for them. Also, since they are used to migrating account data from other publishers, I'm certain that performing a migration would not have been too difficult for them and that it is indeed LG who is blocking the migration (and as I said before - LG said so themselves).
Yes. There are actually people on the forums/discord trying to convince others that this is all Gameforge's fault but it's pretty clear from what LG wrote that they're the ones who are making this decision and hoping people are gullible enough to believe the GDPR excuse or whatever else they come up with.
Either way it seems to speak to the submissive nature of a good chunk of the SW playerbase 
Not worth calling them out directly but even in this thread there was someone roughly saying "You've put up with worse why not put up with this too?" and being totally serious about it.
Learn to have some self-respect.
One last point: The only way you will get anything out of LG is not through appealing to them with reason or emotion. They need to basically be scared that failure to give at least some compensation to GF players would harm their profit. I'm sure they've already weighed the pros/cons but decided they rather launch as attractive as possible for those day 1 mega whales. So really the only solution is a major social media campaign to shake things up. That said the likelihood of success is low.