The 76-year-old became known as 'King John' as a result of his play at first five-eighths during a tour in which he scored 180 points for the side who claimed a 2-1 series win, with one drawn, over the All Blacks in 1971. It remains the only series win by the Lions in New Zealand.
John told The Rugby Paper, "I would not play rugby now. That is not to say the game was better when I played: it is merely different today, more regimented with coaches for everything and people telling you what to eat and where to be.
"I would be expected to work out in the gym and that would not be for me. Outside-halves are expected to feature high on the tackle list now, but I regarded that as taking work away from the wing forwards," he said.
John, whose ability at tactical kicking accounted for the career of All Blacks fullback Fergie McCormick who he ran all over Carisbrook in the Lions' 9-3 first Test victory – McCormick's last Test, said, "Kicking now is seen as an aerial battle, but there is no point in putting the ball in the air if it plays to the strength of the fullback and brings him into the game.
"McCormick was good in the air, so there was no point in giving him catching practice. I kept it on the ground and he was less comfortable with that.
"New Zealand picked their side for the second Test at the dinner that night, two weeks away. McCormick was dropped, even though the next match was on his home ground, and I spent the evening making sure I did not bump into him," he said.
John said he had looked forward to the tour, especially after his experience when Wales were humbled on their short tour two years earlier.
When the team for the 1971 tour was announced, John said he told coach Carwyn James he had made a mistake when naming Irishman Mike Gibson as the second first five-eighths in the team. John believed Gibson needed to be outside him in the Test team.
That was where Gibson played, adding lustre to a backline with Gareth Edwards at halfback, captain John Dawes at centre, wings John Bevan and David Duckham and JPR Williams at fullback.
John said he enjoyed the challenge of working out in a game what the best plan of attack should be. He highlighted that process when it was applied in the 47-9 rout of Wellington – a game that forced a complete rethink in the way Wellington played the game.
"Early on the 1971 tour, we played Wellington. We were near our line and I watched the way they had lined up in defence. I told Sid [Dawes] and Mike to get ready for a pop pass. Mike was unsure because we were near our line but I went ahead with it and away he went, linking with John Bevan who finished off from 40 yards.
"That, to me, is what rugby is about, not carrying out something because it is part of a plan, but reacting to what you see in front of you.
"As a player then, you had freedom and Carwyn encouraged you to play your game," he said.
John was 27 when he retired, eight months after the New Zealand tour.