Especially if you are skipping Epcot and have more time, I would plan for a full day at HS. With boys 4 & 7 who are into Star Wars, they are likely to love the park. I'm not sure if Star Tours still has different videos they play through the ride (perhaps someone else will chime in on this), but if so, your kids might want to ride that more than once (of course if the 4 yo is tall enough). When are you going?
Things that might interest 4 & 7 yo boys:
- Jedi Training
- Watching the March of the First Order
- Star Tours (40in height)
- Meet and greets with Kylo Ren, Chewie, BB8
- Checking out Star Wars Launch Bay with cool artifacts and memorabilia from the movies
- SW Launch Bay Theater Behind the Scenes movie
- Path of the Jedi short film
- A Galaxy Far, Far Away stage show
- Sampling Star Wars themed snacks
- Tower of Terror (40in height- may be scary for 4 yo, but he may love it)
- Rockin Rollercoaster (48in height- obviously not for 4 yo)
- Star Wars fireworks
- Muppet Vision3d
- Toy Story Midway Mania
- Meeting Buzz and Woody
- Would the 4 yo like the Disney Jr show?
- Indiana Jones show
- Meet Cruz Ramirez from Cars
- If Toy Story Land will be open, then you'd have all of that to explore as well
- Sci Fi dine in is a blast with kids that age
Our last trip was with a 7 yo girl and a not quite 2 yo boy. The 7 yo isn't into Star Wars (2 yo had no prior exposure to it). We spent 10.5 hrs at the Studios and still didn't see/ do everything we wanted to. Granted, we did have to use rider swap for the big rides and deal with diaper changes which takes extra time, but I was truly surprised at how much there really was to do there. So many people on here knock the Studios, but we found plenty to occupy a full day and like I said, we ran out of time to do everything! Frankly, if I had two boys into Star Wars, I would consider at least 1.5 days there, especially of you're considering having them do Jedi Training which can take up a little bit of time. With you only having 4 park days, and not wanting to do Epcot, if I were in your shoes, I would do 1 day AK, 1.5 day MK, 1.5 day HS. If you don't have hoppers, I would plan the first 3 days with one at each park and leave the last open for whatever you decide then that you want to return to. You could always schedule fastpasses for whatever park now and try to change them later on.