"Requirements" may be a little misleading, "possible diagnoses" I think may be more accurate. I say that because Daffodils, compared to other garden plants, don't really require much. However, when their basic needs are no longer being met, blind bulbs result. Sounds like you've taken care of the problem though. Sometimes when I divide Daffodils, blooms may be a little sparse the first spring afterwords, but after that they show renewed vigor. Just wanted to mention that in case blooms still appear to be scant in spring; if they're getting enough sun, you'll likely see tons of color next year.
