One of the things that I believe affects entries (or quality of entries), is themed competitions. Consider that aside from larger Kingdom events, people often do not plan to attend something months in advance. Many arts require much planning before you can even start on a project that could take weeks, or months, to finish. When the competitions have themes, that automatically limits entries to those who are planning to attend well in advance, or to those who can craft something (and accompanying documentation) in short time or to those who just happen to have something that fits the theme.
I thought this, perhaps, was just my own line of thinking on the matter, but when I queried my Facebook friends about it last night, everyone who responded felt the same (the exception being "unfinished item" type themes, because, heck, we all have those). One person even stated that one piece she entered had the worst documentation she had ever written because there simply was no time to do the proper research.
I have also seen people re-write a few lines in their documentation to make an item fit a theme, and sometimes that can be a stretch to the point of sounding ridiculous.
I think people should be encouraged to enter displays and competitions as much as possible. People should be showing off their art and getting feedback! Yet, if they are constantly held back from entering because of themes there are so many missed opportunities for both themselves as artisans and from the populace who could be inspired by their work.