Arsenal broke their transfer record to sign Ozil for £42.4million from Real Madrid on transfer deadline day, and the capture of the Germany midfielder has been compared to that of Bergkamp, who Rioch signed from Inter Milan when in charge of the Gunners in 1995.
Bergkamp, like Ozil, was a club-record purchase and a player with his best years ahead of him.
However, while Rioch understands the comparison for those reasons, he has pointed out the two are very different players.
He told Sky Sports News Radio: "He (Ozil) is a very talented player and I think he suits the style that Arsenal have at this time. He's what I would call a silky player, but he's more of a creator than a goalscorer.
"To compare him to Dennis Bergkamp would be wrong because Dennis was a goalscorer as well as a creator, but it's a huge signing.
"He's a one in six goalscorer but he is a creator. He's very silky, very clever on the ball and has a high ratio of assists, that's what he brings to the club.
"But you've got to have goalscorers and that's the key for Arsenal. For what he (Ozil) creates, can they finish?"
Rioch does, however, believe Ozil will make a huge difference for Arsenal this season.
"He's a good age," Rioch added. "He's coming up to the peak of his career, and I think he'll settle in quite quickly because he's got two German colleagues at the club in (Per) Mertesacker and (Lukas) Podolski.
"He's going to an outstanding club, and they're a good football team. They've had a lot of criticism with not going into the transfer market but they've started the season well.
"They've got a lot of creative players in the side and they've got a lot of pace in key areas. If you've got a passer who can see the runners then you've got a chance, and Ozil is a good player.
"He's exciting in possession, and whenever I've watched him on the TV for Real Madrid I've enjoyed watching him. He's one of those players that you'd want to have in your team rather than play against."
Despite the signing, Rioch still believes his former club are short of a proven goalscorer to challenge for the Premier League title.
"They're definitely a top-four team," Rioch said. "If they had Thierry Henry or Ian Wright in their team I'd say they'd be a top-two team, but it's the goals.
"You've got to be scoring around 80 goals a season on a regular basis and I just wonder whether they've got enough strikers at the club to score those goals.
"You look at the midfield, there's some good players there, and they've added a very, very good player. He will make the team better. It's whether they've got the ammunition and the goals to go into the top two."