We had passes for years to the Busch parks (Busch Gardens and Sea World) and to Universal. Passes for both combined cost less than AP's to WDW, and gave us more parks and more experiences than WDW. We did eventually get to WDW just before I started working there, but on a tight budget, which I totally understand, we got much more bang for our buck going to Uni and Busch.
And they are all great parks. One of the blessings of living in the area is you don't have to really worry about a sub par park like Six Flags or Cedar Fair. They're all great in that area, including Legoland. It sounds like you haven't explored those other parks as well, and I would encourage you to find a way to do so. I have a feeling that your family will likely like all of those as much as Disney- especially with lower crowds.
We love Universal, and made sure that I was able to take my daughter there on our trip last month (the vlog is posted if you want to see and get a little idea of what the park is like) There are places where it can be a bit loud, such as some parts of City Walk, or Marvel Island, but there are many relaxing and quiet areas as well. And lot of small, hidden things to find and explore that many miss. Back before Potter, we were still able to fill out full days at each park with a couple of rerides here and there and exploring around. And with Potter there are all sorts of things to find there. You could likely spend most of a day in Hogsmeade or Diagon Alley without even leaving that part of the park.
I also don't get the complaints about food. The food at the Universal parks has always been pretty good. Even the burgers were decent, and especially for a theme park, but there is so much more to eat there, and that's where you'll find the good fixings. Three Broomsticks, Mythos, Leaky Cauldron, Circus Mcgurkus, Bumblebee's tacos... we loved them all. I wish I'd had more time to eat at other places. But if you really don't want to eat in the park, Burger King, Moes, Cinnabon and other places are in City Walk.
The big question as others have said is how your child will react to the park. It's a different atmosphere- not better or worse in my opinion, just different. Its rides do tend to have more a "thrill" factor than most of the Disney rides, and what they are based on is of course different. They do have character meet and greets- I don't think they are quite the same quality as Disney's, but they are fun. And all of the special events certainly make for a lot of fun, with the parades and other things that they do.
If it were me, I'd take the year and explore the other parks. If you don't like it as much, then go back with Disney later on. Or try some of the others. But there is so much to see and do in Orlando, I wouldn't limit yourselves to just one. You'll miss so much that is worth seeing.
And ignore the people posting who've never been there. I never understood people who liked to jump on threads they know nothing about and pretty much brag about their ignorance. ¯\(ツ)/¯