Any question answered...

I have a road bike with shimano 600 dual pivot brakes and I have been really appalled at the weak as piss braking.

I have a old beater with chrome rims and single pivot brakes, and it stops sharper than the road bike which has dual pivot brakes, shimano pads (like new) a CXP33 rim on the back (machined surface has worn down and become concave) and ive tried both a open4cd and a campag omega v on the front.

Everything feels similarly weak. I dont really get it.

Ive tried friends bikes which have generic tektro (or worse) road brakes with basic cheapy pads, but they feel dead sharp almost like v-brakes.

Why cant I get this stopping power?

Look at cleaning the pads and rims. I would use brake cleaner to clean the debris off. Or a non abrasive cleaner such as cif. I might even give the pads a scrub with hot soapy water and a toothbrush.