We've had this discussion before on TMA and I actually don't think it's a naff idea at all - no worse than lighting up Cathedrals - that most people have probably come to accept as very nice despite initial fears of naffness. Why is SH more in need of protecting it's dignity than York Minster? It ain't is it?
Three things - it wouldn't have to be every night, just occasionally; it could be a big money spinner (it could happen with music events etc - and the heritage sector is totally, totally skint; and, since it would be lighting up what would mostly have been invisible to the ancients, it wouldn't be disrespecting what they created.
So yes, I'd like it occasionally, and I'd go. Having said that, if it causes road accidents then that's that, it can't happen.