Watson was a decent opener, my issue with him was he never seemed to settle. Whether he was on 2, 22, 52 or 92 there was always a real chance he’d get out next ball. His conversion rate of 50s into 100s reflects this (4 centuries after reaching 50 on 28 occasions). You want your openers to really go on with a start and he rarely did.
That said we were really unspoiled for choice with batsmen in general during those years let alone openers. Clarke proper carried us, it’s no surprise he had a dodgey back.