Our family has been visiting WDW during Thanksgiving Week since 1995. Our last trip was this past November from the Sat. before to the Sat. after ThD. We did find that it was more crowded than in years past. But we just adjusted our plans where needed and were still able to have a great week.
A few tips we discovered....
EMH's: We found that it worked better for us to utilize the AM/EMH and forgo the PM/EMH. This was discovered after spending an evening packed into D-MGMS (now DHS). Luckily it was at the first of our week so we were able to adjust our plans. We had planned to go to AK to ride EE during it's PM/EMH, but instead headed over the next night when it was open until 8pm. As we arrived it was 1 hour til closing and as we entered the park it seemed everyone else was leaving. There was a very short line at EE and we were able to ride it 2x's in a row. We then rode a few other rides before deciding to head on over to MK as they were open til 12pm. We got to Mk in time to get a snack and find a great little spot to view Wishes! (our little secret spot actually). We rode several rides there before heading out to beat the crowds to the buses.
In contrast, we had great success during the AM/EMH. On ThD it was EMH-M at MK. We got to do everything we wanted, then popped over to Chef Mickey's for breakfast (which was GREAT), headed to MGM from there til mid-afternoon, back to the resort for a rest and refresh and on to MK for the rest of the evening. It turned out to be a great plan. The next day we were back at MK at opening. There was almost no one there. We were able to ride SM 6 times in a row in 20 minutes.
BUSES: We heard several people complaining about buses during the week. Our friends were staying at POR and had alot of bus issues. We stayed at A-SS and had no problems getting to the parks but found very long lines at the end of the day. Our solution...we just looked for a bus to another All-Star resort (music or movies) and hopped on it. There was usually a very short line and most of the time no line. It was just a short walk over to our resort and at least we were able to sit down on the bus.
I agree that it is important to make your PS requests early and use your FastPasses. And most importantly, do your homework about the hours, closings, new stuff, etc. for the time you are going and have a plan in place. But be flexible when you get there, try to have backup plans, or at least when you see that something you had planned maynot be a good idea at the time, move on to something else. You will probably always be able to go back at another time and do it later during your trip.
Good Luck in your planning and I hope you have a great trip!