Well ... it's more like Sammy Owing Sega now.
Sammy might look like a small developer to you, but their other businesses are huge, and since Sega sucking right now, so Sammy is actually larger than Sega.
So it's not Sega getting Guilty Gear X, it's more like Sammy getting Sonic, PDO, PSO, so and so. and the SEGA Name.
in some ways it's kinda like Enix buying Square, where Enix wants to use Squares name so they call it a merger.