As a frequent WDW and DL goer lately, I do not think in anyway DL will disappoint! Because it is so jam packed, you walk a lot less, and theus get thorough everything faster, but there are a ton of rides there!
And right now, the place looks brand new. They redid everything for the 50th and are keeping it very nice.
Tomorrowland would be the only big disappointment - with the closed PeopleMover track, identical Honey I Shrunk the Audience and rotating (but kind of boring) Innoventions. Although you do have a perfect Space Mountain and a much cuter Autopia. When the subs come back, it'll be getting there for sure.
The biggest shock is how small the castle is. But if you camp out in front of it on a night with their amazing fireworks, you'll think it fits right in.
They did learn a lot about crowds after
Disneyland, so there are bottlenecks in the park. I also find the queque for Storybookland ridicluously narrow - obviously thought it would be all kids with their 1950's thin mommies!
The weather is great most of the time, and never as oppressive as Florida can get. No mistake, after 2-3 days, you would run out of new things to do (even at a busy time of year), but I can't see how it would disappoint.
There are so many nice little details to soak in that I think go beyond the level of attention at WDW.
WDW gives you scale and grandeur, DL gives you intimacy and delight.
Besides, worth it to my mind just to see the real Pirates!