Hi, Jill from my beautiful home state of Alabama!
Our family's first Disney cruise was aboard the Disney Wonder four years ago on the same itinerary as our latest cruise a few weeks ago on the Disney Dream. As far as the crowds are concerned, I did not notice a huge difference on the ship. Obviously, the Disney Dream has greater capacity because the ship is physically 40 percent larger than her two sisters. Therefore, there is more room for all those additional guests to spread out and enjoy the entire ship.
You will more than likely experience a wait for the AquaDuck, possibly a little longer lines to see characters or perhaps at the buffets on the first and last days. Yet, Disney did a wonderful job of making the ship opulent yet intimate. I was so proud to pull into ports as other cruise line's guests looked at our ship with awe and amazement!
I did notice a difference in the sheer number of guests in the terminal on Embarkation/Disembarkation Day and somewhat at the ports of call. The only advice I would give you in that regard is to plan in advance for delays getting on and off the ship. When there are that many people trying to do the same thing at the same time, you can expect some lines and waiting. In addition, I was amazed at guests who lined up outside their assigned restaurant for dinner as much as 20-30 minutes in advance. I figured that they weren't going to give my table away. So, we would wait until about 10 minutes after our seating and show up fashionably late!
I hope this helps you plan. Have a wonderful Alabama day and a magical vacation. Bon voyage!
Andi