I really don't think they'll be trying to do a lot of joint projects. Maybe once or twice just to see how the audience takes it. And I doubt even more that they'd just absorb the company entirely. Parent companies actually give their subsidiaries a lot of leeway, as long as they keep making money. And generally, companies that don't make money aren't in danger of ending up in this situation in the first place.

Disney and Marvel don't really try to cater to the same market. If they did, then yeah, then you could kiss Marvel good bye. This is just a way for Disney to make money off of Marvel's market.

I'd watch what happens before freaking out too hard.