Absolutely take it. I'm betting you will be using it. If you aren't, you can always park it somewhere, or leave it in the room. DD didn't set foot in the stroller from the time she was 12 months old and took her first steps...not at the zoo, not at the mall, etc...except at WDW. At her first trip at age 2 and 10 months, she took one look at the size of WDW and jumped right in. We used it at age 3, 4, and 5 too. We thought about not taking it at age 5, but she specifically asked for it, and boy were were glad we had it. We did DL this summer with her at age 6 without a stroller for the first time, and boy was it rough and slow compared to the stroller days. We will be doing WDW again before she turns 7, and I have to say I'm a little bit worried about what it is going to be like for a week without a stroller.
Ours was a MacClaren and it was great for WDW and DL. One suggestion is that even if yours is an uncommon pattern, tie ribbons or something to it because there will be another identical one somewhere. Ours was a pink polka dot pattern that was pretty unusual but we still saw identical ones parked in stroller parking on a couple of occasions.