Listen, I know we all like to criticize Arad from time to time, but we also have to acknowledge that his actions and selling off the film rights to the characters is also part of what helped save the company from ruin.
Because 10-15 years ago, Marvel wouldn't have been able to do this themselves guys. It was because of the X-Men and Spider-Man movies that Marvel was eventually able to set this up and do this themselves. So had the film rights not been sold off, we might not be where we are today.
I interviewed Craig Kyle (comic writer, now Marvel Studios writer and producer, currently working on Thor 3) at Comic-Con some years back, and he told me if not for the 1990's X-Men animated series, they wouldn't be there today. It was the animated series and its massive popularity that gave the X-Men franchise momentum to get a film made and that sort of helped start the snowball effect. And I imagine Avi Arad helped facilitate a lot of those deals.
So selling off the film rights, for better or worse, was necessary to help save Marvel and get it to a point where they could make the films themselves get to this Marvel Cinematic Universe.
Now would it be nice if Marvel had the X-Men, Fantastic Four, and Spider-Man rights back under their banner instead of having them spread out at different studios? The answer is yes. But had the rights not been sold and had X-Men and Spider-Man not proved that these characters could be viable movie franchises, Marvel might not have gotten to this point either.
I think in hindsight, it all had to happen this way. For better or worse.