Taking a child this young is more for you than the child. You'll have great pictures and memories. The child, not so much. Studies now suggest that infantile amnesia lasts for most kids until age 4. Specific, detailed recall may not be accurate until age 7. In cases with multiple children of varying or gapped ages I can understand how you wouldn't want to limit a family vacation. But that's not really what you're talking about in your post, so.......
There are many attractions that I have no interest in. I get dragged on them anyway. In certain circumstances, they are even forced upon you in the form of an unwanted fastpass. You are right in saying that MK is the park you find the most "little kid" friendly rides. This complaint is not new. I will counter by saying, it's always been that way. Even before the other 2 parks, MK was for kids and families and Epcot Center was for older children and adults. DHS joined in as "the Studios" park and slowly added attractions for teens and adults. Finally we added in AK and it's lovely DinoLand area of misery.
Compared to it's older brother in Anaheim, WDW is just flat out lacking attractions. I haven't actually counted in a while, but last time I did DLR had 1 or 2 more total attractions than all 4 of the WDW parks. So you got more for less at DLR. (The attraction count may be different now but not by very much.) You are just not getting enough at the 2 "newer" parks. I would say you only get the same bang for the buck in MK, but that is opinion.
I do know that there "seems" to be more for all ages at DLR's 2 parks.
*1023*