I understand the monetary allure of a long WDW vacation. After paying for a 5-day ticket, each additional day is only $11 per day (up to 10 days total). However, IMO Universal Orlando Resort has an even better ticket, the 14-day 3-park unlimited visit ticket. After paying the equivalent of two 1-day tickets, you get unlimited "park-hopping" admission to both Islands of Adventure (with WWoHP) and Universal Studios theme parks and Wet 'N Wild water park for 14 days as well as no cover charges at City Walk clubs. Quite a good deal.
As for which resort complex was more appealing, here is a short summary of a recent trip. I just spent 6 days/5 nights in Orlando (came home Wednesday) with a friend and his family (wife and 8 & 10 yr old girls) who were doing their 1st Orlando trip (14 days). I live in FL and go often. Here are some observations. Three days at Disney, 3 days at Universal. They did 2 WDW parks before I joined them and did WDW and UOR after I left.
They found Universal much more fun and engaging. They were big readers that loved Harry Potter and were completely taken by WWoHP. The girls also loved roller coasters and loved Dragon Challenge (did both), Hippogriff, The Hulk and Hollywood Rip Ride Rocket. Loved Transformers, Spiderman and Forbidden Journey too. Parents were not thrill ride fans so I was 'forced' to go on those rides with them. They found the Disney parks rides tame and so-so except for Rock n' Roller Coaster and Space Mountain. They liked the Disney shows but were not Disney-centric girls so princesses did not interest them. It was nice being around young kids that were more literary stimulated and less visually stimulated. The girls enjoyed the KidCot stuff though and we needed to prod them to move on. Didn't do Tower of Terror or Revenge of the Mummy, parent decision, too scary. The parents differentiated between "scary" and "thrilling" so the coasters were OK with them even if they declined to ride most of them their selves. Overall, they were pleased the most with the 2 Universal parks and were happy they got the UOR 14-day 3-park pass in addition to the 7-day 1-park per day WDW Magic Your Way ticket.
As for what these parks will offer in 2017, UOR will have many new and exciting attractions and themed lands. Along with the new Transformers ride and the Simpson's Springfield land, there will be a new London area of WWoHP, Hogwarts Express connecting the 2 theme parks, revamped Jurassic Park area and probably an expanded Hogsmead section of WWoHP. WDW will have a completed New Fantasyland at MK and maybe an Avatar land at DAK (no ground-breaking yet). Star Wars land at DHS will probably be under construction. Because of this, I said you may have far too much Disney planned and far too little Universal planned.