These threads have been very enjoyable - thanks to the OP for providing such thoughtful topics.
To me - and to some unquantifiable number of other fans - some of this perceived lack of difficulty comes from what visually looks to be not difficult. When you watch the examples of breakneck Cadets or Cavies drill moves from the past that are combined with electrifying music, and then they hit a set with a music impact, it looks more difficult than a corps jazz trotting to a blob set for a quick music hit while the guard is performing individual movements, tosses, etc....to be followed by the same (yes, I know the previous is an oversimplification). Furthermore, the lack of unison movement (feet, body, equipment, etc.) contributes to the feel of what is being done now not seeming difficult. Even though we know that it isn't haphazard and random, it appears to be - it looks fuzzy, unformed, imprecise - which I guess can easily contribute to the impression of not being difficult. I must confess to wanting more field visual "WOW" moments (e.g. SCV 17 flag visual) to go along with the incredible musical performance we're being treated to. Emphasizing the individual visual movement at the expense of unison movement takes away some of the feel of excellence that drum corps has always had...to me....but I still love it