In five years, the CD's and DVD's you burned may be corrupt. Optical discs' quality isn't what it used to be. Of course, this varies from manufacturer to manufacturer. If you want to digitally store data, the most future-proof way would probably be to use multiple good quality SD cards.
If I was to send myself payments to this address and in 5 years for example -- I would place wallet.dat back into another Bitcoin wallet, would it catch-up and find all the payments that were ever sent to that wallet?
Keeping wallet.dat for long term storage is not a good idea. Although you will be able to extract your private keys even if the wallet.dat format changes in the future, it would be better to generate your private keys using vanitygen or bitaddress.org software (offline!) and store them into paper.