One challenge is that his camp will likely demand/expect max. As of now, I don't see him as that level of player, but if he demands it, can we afford to let him walk for nothing after the price we paid to get him?
Teams would like to avoid such players get to final years of their contract, and an extension is often negotiated ahead. If he gets to the final year of his contract, at least some of the offers will dry up, as teams will hope they can sign him for free. Trading teams also fear that he might not sign long term (though back channel negotiations allow them to get a pulse on the situation). Some of the teams at least might fear this, and may not offer too much.