BDB is still used for the wallets. Making it optional for the blockchain had far too much testing risk, as inconsistencies in blockchain behavior across the network can cause forking problems. Testing just one backed was already hard enough.
Six hours sounds like a redownload, not a reindex. Can you provide more information about your OS and hardware?
bitcoin also no longer works well when I tell it to store all the data files on my NAS as I like to do from my laptops
Yes, this is a known (but not known at the time of 0.8.0's release) issue.
I think it would be less risk to have as a fall back then to force all new clients to use a new db engine, especially since you can't force everyone to update at once, it gives you a fall back if issues arise in the new engine behaving differently without having to lose any other improvements. Ah well, too late for that either way.
I actually think I could re-download faster then six hours. I definitely could with the older version but 0.8.1 is much slower.
The software itself says it is reindexing blocks on disk.. while this happens.
The issue is on my windows 7 64bit laptop, i7 Q 820 processor, 8gb ram. NAS is a synology. Works well still with alt chains, but no longer with bitcoin. Any other details that may help?