Epcot underwent one of the most aggressive periods of E Ticket building in Disney Parks history. From 1999 to 2005 3 new E Tickets opened. Soarin finished those updates. Epcot has been living off the momentum of those upgrades ever since. I would say it's time for serious thought on updating Future World extensively. However, it's not critical. That's the problem. Despite being older, there are enough crowd pleasers to make updating and spending more seem illogical. How many more guests could Disney gain by adding an all new E Ticket? The jury is out.
I don't know if they need to gain more guests to Epcot, specifically, but they do need to disperse their guests, and they need to keep their guests from just wanting to spend a few days at MK then go over to Universal. Honestly, this is what I see our family doing once all the kids are school-aged.