To echo the sentiments already expressed, these are a time consuming, thought provoking, difficult to write administrative burden. However, I have put as much effort into drafting these for my CO as I have for every report I've written.
I hope that they're continued and any Sqn Cdr worth his salt should continue to send these, regardless of the 'requirement'.
Incidentally, my Boss sends these to people who aren't technically 'entitled' to them when leaving (PVR, options etc) which I think is excellent work.
Come to think of it, can I swap my extra fitness test per year to spend a couple of hours writing valedictories?
