Probably a big part of thinking how quick they are had something to do with the fact if you got hit in the head, you probably ended up in hospital whereas today batsmen have helmets.
Good point. Didn't Rodney Hogg kill Ewan Chattfield for a minute or so? (He was revived on the ground.) He wasn't exactly express.
I don't think there's much difference between old and new. You can only run in and roll your arm over so fast. I think there were express bowlers, Andy Roberts, Thommo, etc that were comparable in speed to modern day bowlers.
I don't put much stock in that World's Fastest Bowler thing. Unless you tested Brett Lee and Shoaib with the exact same speed-gun, using the exact same calibration, in the exact same weather conditions, its doesn't really work for comparison purposes.
To think of it another way - we've all seen footage of Lillee and Holding, great actions both - would anyone here honestly say they weren't fast enough that they would face them without a helmet?
edit : just noticed angryangy already made my point about speed-guns.