If Warhammer goes the same way, I'm not going to unilaterally throw all my 40k stuff away

That's not what I'm suggesting. I'm suggesting you throw it all away NOW.

If Warhammer goes the same way, I'm not going to unilaterally throw all my 40k stuff away

That's not what I'm suggesting. I'm suggesting you throw it all away NOW.

there's 40+ years of rulesets

And yet you haven't bothered to create an open branch project. Understand this about RPGs: MODE OF OPERATION CANNOT BE COPYWRITTEN. Games Workshop can copyright and trademark their books, characters, designs, and art. But the actual rules, can only be patented and they don't have a patent.

You could take Games Workshop's rules, create a white room clone of it, and they would lose if they tried to sue you over it.

If Warhammer goes the same way, I'm not going to unilaterally throw all my 40k stuff away

That's not what I'm suggesting. I'm suggesting you throw it all away NOW.