I think the disagreement here lies in the definition of ATG.
Do you base it on who is the greatest talent wise - quality of stroke play, how good they looked, their capability to dominate...or do you base it on those who have proven records all over the world, who have scored the runs time and time again, who are proven performers at the highest level.
All the rhetoric about Barry Richards is centered around how brilliant he looked. The ease with which he hit the ball, his array of shots, the elegance of his strokeplay, the way he could dominate the best bowling of his day. And that is to be backed up with one good Test series, and a fantastic FC record.
But a lot of the same could be said for a player like Vinod Kambli. Incredible FC record, immensely talented batsman, some would say he was better than Sachin. But he didn't perform to that talent at the Test level. Had he been banned from playing cricket after the amazing start to his Test career, we could easily talk of him the same way we talk of Barry Richards. But we don't. Because he was given the opportunity to keep playing Tests, and we saw the mental frailties he possessed, and he eventually slipped out of the team and out of contention for All Time Greatness.
Who's to say that if Barry Richards was offered the same opportunities, that he wouldn't return the same results? What if he turned out to be another FC giant and Test Match muppet? What if he couldn't handle the pressure, didn't have the temperament? What if his talent abandoned him at the highest level?
A lot of players have incredible FC records. A LOT. But we don't classify them all as ATGs. Many of them have failed at Tests. And personally, while I respect the talent Barry Richard is claimed to have possessed, I won't consider him for ATG status. Because to me, being immensely talented is not enough to be considered an ATG. What you do with that talent matters just as much, if not more. And yes, Barry Richards was unlucky to not have more opportunities to display his abundant talent. He might have, for all we known, been the best batsman to have walked on Earth since Bradman. At the same time, he might have, for all we known, have just been an earlier version of Kambli.
Having said all this...Pujara, WAG.