To me it's all about balance - Having the ability and gusto to go for the right free agents, the right trades, and not ignoring things like chemistry, and the quality of the player as a ballplayer, and as an individual.
The Blue Jays have had some smart maneuvering, and quality drafting pay off. They were in a position where they saw some quality prospects, like d'Arnaud, Nicolino, etc. that were variables distances away from helping the team, and they decided to "go for it", but they didn't go hogwild like we've seen the Sox, Dodgers, and Yankees do. To me, what the Jays did was smart, and seems quite balanced. How the team gels remains to be seen, but they appear to be awfully good.
I love what Boston is doing. You can't expect EVERY youngster to pan out and be a quality big leaguer, it just doesn't happen.
With short term contracts (Napoli, Victorino, Ortiz, Dempster, so on.) they've set themselves up to be competitive while still maintaining their plan of developing quality young players to mix in to the team, all while holding a hand full of aces if the right trade presents it's self.
Now, this is just completely hypothetical, off of the top of my head, but..
Let's say it's 2 years from right now and a few of the better prospects have worked out, others are on the cusp, or are viewed as "change of scenery" type players. Maybe the team can parlay some of the youngsters in to, let's say, a Troy Tulowitzki, just for the sake of argument.
You'd have a lineup of cost controlled talent - Middlebrooks, Bogaerts, JBJ, and then could trade a few players that are blocked at the MLB level for someone dynamic.
Having those "chips" on the table means everything when it comes to long term building.