"Now I can say no (to Wes), because we have our system because we have Robbie Keane, Long and Cox. We have two strikers in our system. We need more weight in the attack," said Trapattoni.
"We tried in the past with James McCarthy, we tried with (James) McClean. It is not easy to change this system when they play a different system in their clubs," he added.
Trapattoni has signalled that he is ready to welcome Darron Gibson back into his squad but not before the Derryman makes his intentions plain.
"Darron Gibson? I spoke with him. He must be fit and he must say, 'I am available'," claimed Trapattoni.
Trapattoni watched Sweden deal with England in midweek and has plenty of respect for a team clearly on an upward curve.
"We know Sweden very well. They have had the same team for a while. They play for clubs across Europe. But we have to think we can beat them.
"Ibrahimovich scored a fantastic goal, but they also have good defenders and centre-backs. But I will say that no team is unbeatable. The Champions League showed that when Celtic won against Barcelona."
Trapattoni claims to be delighted with what he saw against Greece and focused very specifically on Seamus Coleman as the star turn.
"Coleman was the player of the match. He confirmed his strength, quality and attitude without any fear. He is very, very important this man.
"But Coleman plays every game in his club. He grows in every game. James McCarthy? I like him but he can be physically more strong. It's not just physical it's the responsibility of the player for playing for his country."
Trapattoni is keen to talk to both UEFA and FIFA about the weighting given to friendly games in the FIFA rankings.
If he gets his way, friendly games will no longer count in the ranking which he believes would free up international managers to experiment more.
"I wish to propose to UEFA and FIFA that the ranking stays the same after friendly games. I have spoken to them to them in Nyon and Zurich.
"It would be good if the national teams were allowed to try young players without having to worry about rankings."