Thanks for the suggestion! I had the exact same same ideas of dropping the last line and whether to break before or after "suddenly". I'm still not sure, so I'm just letting it sit for now. I have a lot of haiku like that. They say that one of the reasons Bashō wrote relatively few haiku compared to others is because he would continue to work on haiku for weeks and months, trying to get it perfect. I can understand that urge!
The middletown studies are interesting. I've heard all kinds of reasons why my hometown was picked, but it probably boils down to just randomly picking a city that met certain criteria. The wikipedia write-up gives a decent summery if you are interested: https://en.wikipedia.org/wiki/Middletown_studies