Clevelend needs to trade Ilgauskas for young talent and expiring contracts, as long as the young talent fits Bron better than Big Z. Their goal should not be to win now, but to win in 3 to 4 years. And a team that features Hughes and Big Z as the secondary stars ain't gonna win a championship, so they should look to trade tham as soon as possible and try to acquire talent and develop it. With Bron they have a huge window, he alone guarantees more than a decade in the playoffs.
Another thing is, having Ilgauskas on the team may make them win 50+ games, but they won't stand a chance against WC teams. So they'd be better of getting 7th or 8th seeds, or even being in the lottery to get good draftpicks, increasing the chance for Bron to get his Pippen