IMO, many people underestimate the # of days to spend at DLR. There's almost as many rides at DLR in 2 parks as there are in 4 parks at WDW. Most people say 3 days is enough for DLR, but (IMO), that requires a pretty fast pace** and would definitely be difficult with any crowds.
We went in 2015 and 2016 (November, for the Avengers 1/2 marathon both years). In 2015, our trip was Friday to Friday, and we were in the parks for 4 full days (2 days in San Diego) In 2016 our trip was Tues-Tues (6 days in DLR only). In both years, we got the most done on the Wednesday/Thursdays of our trips. We felt rushed in 2015, though, when it came to
Disneyland...there was a lot we didn't get to, especially in DCA.
The 2 extra days we had in 2016 made a huge difference = *especially* because of the Marathon/Opening of the Holiday season weekend in both years. Once the runDisney events started, the parks were *packed,* and yeah it was harder to get some things done. We learned our lesson with that in 2015. The extra days this year allowed us to relax on the runDisney event days. Dh and I both ran the 10K, and he also ran the 1/2 - so we weren't getting to the parks early on those 2 days anyway. So we took our time coming back into the park. We had ADRs for both days, a photo shoot on one of them...rides weren't the focus on Sat/Sun, so the crowds didn't negatively affect us as much.
Because of the 4 parks, differences in transportation times and such, it's harder to take that approach at WDW *AND* get as much done as we did in DLR, with the relaxed pace that we had at DLR both during the low crowd days and higher crowd days.
I love WDW too, and I look forward to taking DD there again at some point. But right now, DLR is a better destination for us.
(**I caveat that to a fast pace with a family. When DH and I were going as just 2 adults, we could knock out DLR in 3 days without a problem...we opened and closed the parks and had a blast. That pace isn't possible with DD

**)