It sounds like your kids are ready for bigger thrills and since you only have a few years left with them, it's time to try something new. Save Disney for when you come back with Grandkids!!! (Too soon?!?)
I typically will eat a small breakfast on the walk over (roll, granola bar, etc.), Counter service lunch in the park, Table service dinner at City Walk. Breakfast is usually $10, Lunch $15, Dinner $30 & Snacks/Drinks/Extra Vacation Desserts, etc. $20. Some days I only spend $35-$40, but $75 is about the max in a day.
Since I'm not a big breakfast eater, I usually have a Dr. Pepper & granola bar in the morning. Easy enough, but I believe the new park restrictions won't allow in opened bottled drinks, so you would have to finish before you hit City Walk.
In the parks, lunch is usually CS & I would recommend eating in Springfield. Between all the counter options inside & the taco truck outside, there is something for everyone. Lots of people speak highly of 3 Broomsticks & Leaky Cauldron, but I haven't tried either, yet. As far as sit down goes, I would recommend the deal for Dinner & Priority Viewing for Cinematic Spectacular...I think it was about $45, but also came with a desert bar. Dinner was very good and we loved not having to fight through a crowd to see the show, but I would recommend an early dinner seating so that you can actually take advantage of the dessert bar, since the dinner included a LOT of food, we didn't get as much out of it as we would have liked, but still thought it was worth the $$.
In City Walk, most of the CS meals are common fast food chains (Burger King, Panda Express, etc) but also have great table service meals. Don't skip Cowfish!!
Also, due to the proximity of the hotels and ease of transportation to City Walk, don't rule out hotel restaurants as well...its not nearly the daunting quest that it can be at Disney to venture to a different hotel. I have loved the Kitchen at HRH!
I don't know if you will be driving or flying, but if you are flying in and only planning on staying at Universal, I would recommend getting a shuttle instead of renting a car because UO hotels charge $22 (last price I saw)/ day for self park, which is a little steep. To help, not have a car rental, you can order groceries through Garden Grocer, which I believe also has free delivery with a $100 order. Get a few cases of water, pop if that's what you drink, Kraft Easy Mac where you just add water and microwave, packages of peanut butter crackers, etc & you can drive that cost down as well.