Paterson will again be a key player in his third World Cup with Scotland and is vying with Dan Parks for the stand-off role following Frank Hadden's announcement of his 30-man squad, which saw Gordon Ross omitted.
Former Edinburgh player Paterson, who recently joined Gloucester, played at number 10 in the 31-21 victory over Ireland last Saturday and feels the squad is shaping up strongly.
The 29-year-old said: "If you had asked me in 2003 I would have said that's the fittest I have been and the strongest the squad has been but things have moved on four years.
"The game has moved on and the science and preparation have moved on four years so we are undoubtedly fitter and in the best shape we have ever been in.
"It's easy to say that and you have to back it up and I think to some extent it was backed up on Saturday (against Ireland). Talking to the Irish guys after the game they were amazed at how fit and how game sharp we were.
"It's the best we have been and it can only help us. However everyone is four years further on from the last World Cup as well."
Victory against South Africa in the final warm-up match would send Scotland into the campaign in a more upbeat mood than they approached the last World Cup in Australia.
Paterson would ideally like to feature in that game but admits preparing the whole squad for the task that awaits them must be the priority.
He said: "Everybody wants game time, that's what you are looking for and that's not directly to do with positions and obviously I would like to get some part of the game.
"But Dan will need game time at 10 as well and other guys will need game time in the back three and I think the whole point of being a squad of 30 now is that everybody prepares as well as they can for the competitive games coming up.
"We spoke a couple of weeks ago about whether two games was too few - if you have more games do you run the risk of injuries? - and I think two is just about right."