Yes it would. There would be substantial risk, but the reward might be worth it. If he stays with the sox for the next 20 yrs, racks up another 2 titles or so and puts a playoff caliber team out there every yr, he's a HOFer. But, if he goes to the Cubs and somehow wins a title, he'd be a HOF candidate right now.
Let's just throw a theoretical out there. If Theo left the sox to go to the cubs, would you all be mad at him or wish him well? And a second theoretical. If Theo came back to beantown as the GM of the cubs, would you boo him or buy him a drink?