Nikau, a key performer when the Storm won their first title in 1999, also expressed doubt over Broncos prop Adam Blair being a wise buy for the Auckland club.
"Too many Warriors players aren't up to first grade standard and that's the major concern," the Kiwi selector told Radio Sport's D'Arcy Waldegrave.
"The Achilles heel is the forward pack - there was no foundation for the spine and outside backs to perform off.
"They struggled all year to contain the middle of the ruck and lay the foundation. But there are a whole lot of pieces to the puzzle, not just one thing.
"I feel sorry for (coach) Steve Kearney at the moment. There has to be some stability so Steve can get the players he wants.
"But it is really hard when you have a team that doesn't perform. How do you attract players to a club at the bottom of the table, with a culture of not knowing how to win, losing for the last 20 years."
Nikau said many Warriors players lacked the required mental toughness, and that Australian clubs only began to rate players as first graders around the 100-game mark.
He urged young Kiwi prospects desperate for notice to head to the proving grounds in Queensland and New South Wales. He inferred the Warriors might recruit from there as well.
Blair, who is still involved in finals football with Brisbane, is rumoured as the next Warriors signing, joining Melbourne's Tohu Harris and Titan Leivaha Pulu at the club next year.
Nikau said: "Whether (Adam Blair) is going to be a good buy...or is he coming for overs (big money) at the end of his career for a three or four year deal."
