I've always been under the impression that it's mainly Virginia dominant blends that age well, burley definitely don't, all due to the sugar content in the leaf.
English blends with a lot of Latakia get more smooth and creamy and less slap you in the face bold also. I got an 8oz tin of some 11 year GL Pease Odyssey from a friend and it's different than any fresh stuff I've had. Not better, not worse, just different.
Some blends are better aged some are better fresh. I figure this is why the old codger burley blends were so popular, to my knowledge burley has a very low sugar content so aging it won't do anything but degrade nicotine.
Im currently smoking some C&D Pegasus from 2018.
Pegasus is just 3 types of burley.
Is this 2018 better than fresh?
I dont know, I fell for this blend years ago when it was "fresh" out of the bag.
It sure isn't any worse..... as far as I can tell.
At this point all my tobacco is aged.
I quit piping for 7 years.
I did buy tobacco during that time, I knew id be back. 2019 was the last time I bought tobacco.
I quit in 2015 and re-started last Spring.