That is some next level alternative history there haha...but I'll play. If Shields pitched the last 4 innings in an epic game 7 for the 2016 World Series Champion White Sox then hell yes the trade was worth it.
Back to real history...the problem I will always have with the Shields trade was that Erik Johnson should have been more than enough to acquire a James Shields who had been called out by the Padres owner for sucking so badly. The fact that Hahn had to throw anyone else in the deal is a joke, The fact it was Tatis borders on a tragedy.