Oh yes I agree with you!
I do only use the 1 runtime with sub folders and I don't want to get into the single or multiple runtime discussion again because we all have our preferred way of working, but when I went from P5 to P6 I did copy a lot of the stuff over but NOT a complete dump of the P5 runtime on top of the P6!
I agree that's not a good idea!

Injustice will be avenged.
Cofiwch Dryweryn.