Speaking before the club's first official pre-season session on Monday, the Swans forward said the five-day trade week period was too long.
"It could be done in one day," he said.
"And I think the structure has to be looked at. I think free agency needs to be looked at. And whether they deal with future draft picks which they do in the States.
"I just think it needs to be reviewed. It's probably the only system in the world that deals like we do and I think it’s had its time."
After last season, O'Keefe told the Swans he wanted to move back home to Melbourne and asked the club to secure a trade with one of the Victorian teams.
That didn't happen and, despite subsequently signing a four-year deal with the Bloods, O'Keefe said the whole process had been frustrating.
"It's frustrating for the clubs as well,” O’Keefe said.
“ I can't speak on behalf of all clubs but from what I've heard, it's pretty frustrating [for them] as well. They wanted to get some deals done and get some other players as well.
"It was very difficult. No deals were getting done, nothing was moving."
Swans’ coach Paul Roos echoed O’Keefe’s thoughts on future draft picks.
"It's difficult to answer but one thing that needs to be looked at is trading future draft picks,” Roos said.
“If you look at the situation, Ryan was keen to go to Carlton but I think they'd already committed pick 24 to (Fremantle's Matthew) Warnock, so it really leaves them with nothing more to trade.
"And we had some good discussions with Carlton and they were pretty honest so there [was] not a lot to actually trade with.
"So I think trading future picks, which I think happens in the US, [the} NFL opens up more options to get players across the line.
"That's one area, but there are other areas to be looked at as well."
