England's domestic league opens with the customary London double header on Saturday week with any one of four teams capable of winning the title.
Leicester start at favourites despite losing in May's final to champions Harlequins, while Saracens and Northampton are also in the hunt.
"It's got tougher every year and there are no easy games," Mallinder said.
"There are sides who usually finish in the top three and they'll be there again, they have strong squads and have good structures.
"Below them are a number of improving mid-table sides who have pushed on a bit. It's going to be more competitive than ever.
"I don't think there are any outstanding teams out there but Leicester, Saracens and Harlequins are three good sides.
"There have been changes at Gloucester and Sale, while Exeter will continue to improve."
Saints were edged 25-23 by Harlequins in last season's semi-finals, conceding a try four minutes from the final whistle to leave them trophyless.
Having reached the Heineken Cup final the previous year, it was a sombre end to the campaign, but Mallinder sees no shame in their performance.
"We were disappointed after losing in the semi-finals," he said.
"You always want to reach the final, but this year's a new year and we've had a good pre-season.
"It did look very promising after reaching the Heineken Cup final in 2011, but we weren't that far off last season.
"We were only a couple of minutes away from beating the eventual winners - and that was with a team missing four or five of our top international players.
"You look back in disappointment, but we took a lot out of it, including younger players getting experience of big match occasions."
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