Regarding your OP, what about royalex canoes we wish we hadn't sold? First one that comes to mind is the Dagger Sojourn. If I had more storage space, I would have never let it go. Probably going to say the same about the Guide....
Not the OP, but here is my list of Royalex canoes that have moved on:
Perception HD-1- Wettest WW boat I ever paddled, but introduced me to OC-1s. Glad it is gone.
Old Town Penobscot 17- Wish it had been a 16; big for me and my wife on day trips. Not too sad about selling.
Old Town Kennebec- A bit of a log. It would float high through the rapids, but not great for quick maneuvering on small rivers. Heavy! No regrets.
Bell Yellowstone Solo- Nice canoe, but it felt small to me at the time. Gone to make room for another canoe, sort of regret selling it.
Bell Yellowstone Tandem- Tandem and solo with a substantial kneeling thwart. I probably should not have traded this one off.
Mad River Explorer- A classic, but a buddy needed a canoe, so I know where it is. Not too sad not to have it in my storage area.
Old Town H2Pro- Nice classic whitewater canoe. If I hadn't upgraded to my Millbrook Outrage I would still have it, but no regrets.
That was a fun trip down memory lane. Before passing judgment, remember that my first Royalex canoe was bought in 1993, so divide the number of canoes by 31 years. I currently only have one Royalex canoe.