Following up on what I just said...I did a quick review of the attractions in Animal Kingdom and Epcot. What constitutes an "attraction" is somewhat subjective, so I included shows and exhibits (such as Launch Bay or AK's animal trails), and then excluded M&Gs, restaurants, and playgrounds. By count alone (disregarding popularity and capacity), I found that DHS and AK have the same number of attractions, while Epcot has only one more than DHS and AK. (Again, there is some subjectivity in what I deemed an attraction, so your count may differ from mine.)
I've not bothered figuring capacity into the equation, as that'd take more time than I have now. Maybe later I'll do a study on that.
Popularity is somewhat subjective, too, although I'd argue that DHS has more attractions that are "popular" (where "popular" means rarely empty and usually with a line or a decent attendance) than Epcot. This is purely from recollection and observation, not a hard study on the subject. AK might edge out DHS on the number of "popular" attractions, but if so, only slightly.