We took our DS last year at that age and he was ok with being in the stroller and hand holding otherwise. It seemed to work ok if we let him "loose" for a little while - like the Pooh playground at MK, which he loved! We took my parents with us, so they were able to help with taking turns holding hands, etc - you know how it can be to deal with a 2 yr old that only wants to hold grandma's hand right now but in 5 mintues, only wants to hold Mommy's hand...
Now, this year when we go back, it will likely be a different story! He's not much for hand holding and doesn't listen well, so we'll consider the "leash". I don't think i'd normally use this at home, but given the crowdsat WDW, I'd probably feel better if I knew he couldn't get away....