“I’m asking a poll question. Should I steer boys away from down sleeping bags and quilts for Philmont?”
Not whatsoever.
As an adviser for a couple treks now, I’ve advocated the opposite, since down is so much lighter, more compressible, and is arguably much more durable over the long term.
In 2014, my son used the exact same 15d down sleeping bag at Philmont that I used back in both my 1988 and 1997 treks. He’s almost an Eagle now, and still uses it as his primary bag. If I had purchased a synthetic bag 30 years ago, it would be a glorified throw rug by now.
(Admittedly, North Face used to have a $25 cleaning service where I would mail them the bag, the would remove the down, clean everything, then re-loft the bag it to it’s original specs. I used that service at least once or twice, if I recall.)
Regarding quilts: while they certainly require a little more finesse to use, I assume there are many 14 year old scouts that are perfectly content with them. Besides, they don’t have any zippers to break!
Of course, you could always ask Ryan Jordan what he recommends to the kids in his Venturing Crew