As I've said before, this is almost a good thing. For starters, we're spared having to watch a boring retread of the irritating courtship arcs of her older siblings, irritating bullshit about how adventure and curiosity are things that must be outgrown, worship of a fair-haired moron who is better for her because John and Elly know who the demeaning and churlish imbecile is and Elly having almost no involvement in the wedding because a vain halfwit thinks that mothers have to take a back seat to the bride.
We also get spared having to realize that Lynn's super-impossible happy future for the characters is a crazy lie. As josephusrex suggests, it's likely that April's chances of being a latter-day James Herriot are rather poor owing to her patented Patterson piss-poor study habits, love of binge drinking when not supervised and low demand for anything other than 'person whose job at the animal shelter involves cleaning out the cages'. As she struggles through grad school and has to endure abusive calls from John about how she shouldn't talk that way to her insistent irritant mother, April will be wishing that she didn't have the Patterson habit of drinking her way through life.