A few thoughts on drill instruction and competency... I'm not going to touch the "role of drill and ceremonial in today's CF" thing, except to say that I can think of no armed force that conducts or conducted operations involving more than company-on-company fights, or technology, strategy, or tactics beyond contemporary banditry, without some sort of shared, non-mission-relevant ceremonial activities, whether it be gathering for a blessing or sacrifice, a formal oath-taking to a commander, or the damned near universal act of tramping about one's home town in whatever passes for No. 1 kit.
Changes of command, unit birthdays, Remembrance Day (and the service- and regiment-specific commemorations) and community parades all have a certain predictability to them. A reasonable run-up to each, with perhaps six hours of drill over the course of a week (a drill-day right before the gig is a waste of time, after the first two or three hours), should maintain the unit's standard of drill to a sufficient level that, should something unexpected crop up, it is not necessary to either turn a blind eye to ham-handed drill, or to spend an unexpected three or four days re-teaching the 201.
As far as smaller events; guards of honour, funeral parties, and so on, where the entire unit is not required to do anything overly complicated, rotate sub-units through the role of having to provide personnel for ceremonial duties on a routine basis. Work up one month, deal with ceremonial tasks the next. Wouldn't take too much time, overall: cadets can be taught how to (badly) conduct basic rifle drill in two hours, well enough to get through Colours without committing any major gaffes, and the predictability might prevent some of the complaints on here regarding disruption of training, operational prep, or whatever.