Add another person who went this year for the 4th (June 28 - July 8) and didn't find it unmanageable. The crowds were nowhere near as bad as I expected after some of what I had read on the boards. A few observations and pieces of advice:
1) I found the crowds to be lighter up until about the 3rd and then it got busier with each day. If you are going the actual week of the 4th next year (not starting on the 4th), I would plan accordingly and try to hit your must dos and things that tend to handle crowds worse earlier in the week instead of later. Since the 4th is a Friday next year, I would expect to see a similar pattern again.
2) Like a pp, I saw the MK fireworks on the 3rd and found that they weren't nearly as crowded as I expected (and much less than they were on the 5th and 7th, but that's another story). Would highly recommend this approach vs. trying to do them on the 4th.
3) Consider seeing the MK fireworks from the Poly beach, I found the view out there preferable to the one being in MK as I was much better able to see the whole show. I did this the night of the 6th, so it wasn't the full 360 show, but still amazing.
4) If you end up doing a park on the 4th, I'd recommend AK or HS. I did AK during the day and the crowds were pretty low. I then jumped to HS around 6 pm, did some rides and dinner there, then settled in for fireworks. Be prepared to stake out a spot and wait a while for fireworks (people were already lining up as I was entering the park), but they did have Mulch, Sweat and Shears playing so the time passed well. Whatever you do, make sure you have a spot before the 9pm Fantasmic show lets out (I still can't figure out where those 10k people went when they exited the show

)
5) If you see a long wait for a ride, skip it and go back later. As an example, on the 5th at MK PotC was at 60 minutes the first time I went by, a few hours later it was 5 minutes.
6) Make use of EMH (both AM and PM). I actually did do the EMH at MK that ended at 3 am (July 3rd, well by 3 am it was July 4th

) and the park was pretty empty from 1-3. Got some great pictures coming down Main St at 3:30. Rope drops were also good, low crowds and I was able to get a lot done in the first few hours.
7) I didn't see many tour groups early in the week (maybe I was lucky), but saw a ton of them later in the week. Try to zig when they zag, no other good way to avoid them that I'm aware of.
8) It will be very hot and humid. Make sure you hydrate accordingly.
9) With the high heat levels, I did see BB closed to capacity a few times that week (can't speak for TL as I didn't go by there). If you are planning a water park, I'd advise either very early or very late in the day arrival.
I had a great time and would go back on the 4th again without hesitation.