Posting here because I think it's more appropriate:
The same reason most card design competitions don't allow card art, or in the case of CDW3, provided it. The main focus is the writing aspect. The last time I put up a poll asking if a comp should be a combo comp, it was pretty soundly rejected, with like 7-1 against in the first day. If more people think and post here that images should be less restricted, or otherwise changed, I'll put up a poll.
Hierarchy? Because:
1) despite the poll's start, that wound up as only 11-8 against
2) 300 words per deck enabled writing-heavy submissions anyways
Not that I disagree with pre-selected images for Yellow Journalism - I think it's a really good idea to have such a framework outside of CDW, plus it fits the theme, and the selection of images available currently is more than sufficient and well-thought out - but in general I don't think how Hierarchy played out should be a reason to avoid hybrid competitions in the future.
In fact, I'd like to see more competitions where participants have a choice between focusing on the primary class of competition, or adding elements of a second. Hierarchy would have been perfect for that if it had been branded as such, for example. Just briefly looking over the submissions, there seems to be some, but not too much, correlation between words-per-deck and votes. So a future deckbuilding competition that allows writing, but doesn't require it, could see a similar pattern - submissions benefiting from writing, but not necessarily needing them.
