Recently at Baseball Prospectus, Jason Parks and the prospect team had this to say about Maikel Franco:
Strengths: Incredibly fast hands at the plate; can square plus velocity; easy plus bat speed; very good present strength; contact is rarely empty; plus power in the bat; smokes mistakes; arm is very strong at third; glove should play as average; big ceiling.
Weaknesses: Swing can get whippy and loose; will chase out of the zone; aggressive approach sets him up for secondary exploitation; well below-average speed; can make plays at third with okay actions, but footwork can get clumsy and first-step is lacking.
I was able to get a look at Franco back in August, and I can agree on a lot of these points. Franco's most distinctive trait as a hitter is his strength and power, as he not only put on an impressive batting practice show, but popped a few during the games as well. One memorable at-bat featured Franco getting a ball towards the end of the bat, but simply muscling the ball out of the park for a home run to left field.
I think Franco is a 6+ raw power guy, with potential for that to play in game if he can refine his hit tool. I worry about his hit tool as he had a tendency to swing at bad pitches, and at higher levels this could lead to more advanced pitchers exploiting this.
In the field he has the physical ability to play a good third base, but he would get sloppy in the field at times, leading to some misplays and not getting to balls he might be able to otherwise. His instincts at the position were well below-average, but I believe that with enough reps that he can develop his fielding to roughly league-average. His plus-arm should also be beneficial to his continued development at the hot corner.
If Franco refines his approach at the plate, and gets some more reps in the field, I think the Phillies could have a long-term solution at the hot corner here. His development path probably has him set to arrive at the Majors in 2015-16, depending on how quickly he is able to work on some of the issues both Parks and I mentioned.