It's easily Barry.
He was hailed by no less than Bradman as the greatest opener of all time. "At least the equal of Hutton and Hobbs"
Lille rated him only behind Viv and Sobers among batsmen he bowled to and in the same tier.
Procter, Gooch, Dickie Bird called him the batsmen period they've ever seen.
Pollock himself said the two best batsmen he had seen in and after his career were Richards and Sobers.
Mark Nicholas ranks him behind only Bradman, Sobers and Tendulkar. Kimber notes that as a batsman, he's top 10 all time.
Bob Willis, John Snow Jeff Thompson called him the best opener they've bowled to, all ahead of Gavaskar.
Barry was acknowledged as the best batsman in the world from.1970, until his namesake took the title in '76. He was the best opener of the '70's, his record vs the best bowlers of his day is unparalleled, triples and doubles vs Snow, Lillee, Procter et al. His record against touring test teams is in the 70's, his record in WSC was comparable only to Viv and Chappell.
Pollock never faced bowlers of the quality that Barry did, definitely not in tests, which shows the overrated nature and status of.
Barry was a Colossus, 9 hundreds before lunch, 300 in a day, the only batsman capable of keeping up with Vivian on the rampage, especially against quality bowling.
His comps were Richards and Sobers, to many his potential was Bradman.
His accolades were many, he makes Willis's all time team, the Cricinfo 2nd XI, Crowe called him the greatest lost war opener, the named him in his 2nd All Time Test team, Gower rates him the 15th best cricketer of all time, if we can be sure of 6 players that we know for sure made Bradman's all time team, they were Barry, himself, Tendulkar, Sobers, Lillee and O'Reilly.
There's a thread here by
@fredfertang , how good was Barry Richards, I recommend to give it a read.
Many here goes against Barry because he bettered players that they preferred and for the fact that I'm the one who pushes him, but that should say more about them than Barry.
He was the most tested and accomplished opening batsman vs great fast bowling in helpful conditions. Yes Hutton took on Lindwall and Miller, and bats alongside Barry in my AT XI, but Barry took on Lillee, Thompson (in his actual prime), Procter, Snow and Willis. He's the only post war batsman to combine a perfect defensive technique and the ability to consistently destroy quality attacks in all conditions. He could do things that literally no one else could.