I think this rumour is possible for Disney's California adventure since their backlot is likely to become Marvel Land after Star Wars land is finished construction and Tower of Terror's placement means it wouldn't fit thematically. But here there is no chance of this happening.
Think about it, even before WDSP was opened the Tower was planned to be the centrepiece of the park, much like the castle in the main park, it'd look weird to have a Marvel ride there. ToT fits the theme of the park better, is much more iconic and has much more staying power than Guardians of the Galaxy. Not to mention DLP doesn't have the budget and would rather spend it elsewhere.
I still think marvel is Backlot bound and as such it would be silly to have the Tower also be marvel.