Dexters, I don't disagree with you if you're defending a (heavier) penalty for razing.
I remember Civ III was pretty off in this respect, when you nuked a town in Civ III you got a huge diplo hit, usually resulting in some other civs immediately declaring war on you. But the nuked city was at least still on the map.
At the same time you could wipe a whole metropole with 1000's of years history off the map in one go, simply by razing it, and nobody even blinked an eye?
This was hugely inconsistent. In any version of Civ you shouldn't be allowed to raze a huge city with a long history just like that without consequences in my view (for the record, it's those ugly in-between towns that the AI puts down later that I'm razing).
But any penalty for razing should be a suitable penalty, reflecting that you've been destroying culture or committing genocide or something. It should perhaps result in a diplo hit, or a loss of influence with friendly city states, or chances of rebellion in other not self-founded towns, you name it, but a management niggle when constructing a national wonder is hardly effective and an unlogical consequence.
The 'need x in all towns' rule has been invented for a different reason, we all know that.