Is this a bad trade?

I would not do this trade. Hafner is solid and is a great source of power but Burrel is less than mediocre. You are giving away 2 top players at their position. Wright is in an early slump and you would definitely be seeling low, Wells is a great 5x5 player right now if you add steals to last years numbers like he is doing this year his number will look a lot like Beltran. Do NOT make this Trade.