Yandy's biggest problem is that despite his frame, he has developed zero in-game power.
Despite finishing last season with a .263 average and .352 OBP%, which is pretty damn good, he ended up with an wRC+ of 86 which puts him 14% below league average as a hitter. This is because he had all of 9 XBH in 179 PA leading to an absolutely paltry SLG% of .327, which would have ranked 4th worst in the majors last year out of 145 qualified hitters.
Now, he was much better with his glove last year than most of us anticipated. But, he needs to at least find the power to be a doubles hitter if he wants to be an everyday player. I'd like to see him in a platoon with Alonso to start the year. I know he doesn't play 1B, but you can either teach him or put EE there when a lefty is on the mound while DH'ing somebody else, and sliding Diaz into the lineup.
In terms of the Gonzalez/Urshela battle. Looking at their MLB numbers, Gonzalez has the edge. Their defensive metrics are similar enough, Urshela definitely has the edge, but Gonzalez still grades out very well. The difference is that Urshela has been absolutely putrid in his 453 MLB plate appearances.
So, I guess it comes down to what you're looking for out of that spot. Urshela's defense at 3B is better than any one thing Gonzalez brings to the table, but Gonzalez brings a lot more things to the table. It comes down to whether or not Tito is going to value the one elite skill or Urshela, or the versatility of Gonzalez.
Personally, I value Urshela more as a late inning defensive sub, but Gonzalez more as a guy who can fill in if someone is hurt or needs a day off. I guess it comes down to what Tito wants out of that role.