Nephew LOVES app, Aunt hates its size

If my 22 month-old nephew sees my iPad, hell come over, say "hi" in a super adorable way and says is: "Elmo? ABC?" I have several free apps for my nephew, but a few weeks ago, I was done with just the A, B and C options with this apps free version. I downloaded the full version, yes, paying the $4.99 cost.
My issue with the full version is the size of the app. My 3rd generation iPad is not just for apps for my nephew, so app size becomes a huge issue when its to the point I have to delete things for system updates!
The really irritating thing is that there is Elmo app update pending and Im only writing this review because its a 600+ MB update! My question to the developers: why on earth is this app already over 700 MB and need a 600 MB update? It seems extremely large when several other apps are just as detailed and are much smaller (including their updates)?

Just got my first smart phone about Elmo Loves ABCs