The trade was always going to look lopsided long term. That's just what happens if you trade an older player for a younger player. When the older players starts naturally slowing down, the younger player looks like the winner.
It would've been the same had Fev played for Brisbane for a couple of years. At first Brisbane would've looked like the winners, but long term Lachie would win out as he would've been playing when Fev retired.
When Juddy retires, there will be those that say we lost the trade, simply because Kennedy is still playing. But it's simply not true. Judd's influence cannot be measure by onfield success.