The Diamondbacks get
Shelby Mller. Arizona was one of many teams interested in Miller, who became the poster child for poor run support during a 24-start winless streak for Atlanta this year. He went 6-17, but had a very good 3.02 ERA for the Braves, and struck out 171 in 205.1 innings. He will join a Diamondbacks rotation that is already radically revamped with the addition of Zack Greinke, and appears to be Greinke, Patrick Corbin, Miller, Robbie Ray and... pick any one from Rubby De La Rosa, Archie Bradley, Chase Anderson and Zack Godley. That's pretty good. Top-to-bottom, it would appear to be the best in the division, and may end up being among the best in the league.
Gabe Speier. Originally a 19th-round draft pick by the Boston Red Sox, left-hander Speier is now with his fourth organization and still hasn't pitched above A-ball. He was dealt from Boston to Detroit as part of the Yoenis Cespedes deal, and was then traded on to Atlanta in the swap for Cameron Maybin. The 20-year-old put up a 2.86 ERA with Atlanta's A-ball affiliate in West Michigan, over 33 games. He had a K:BB ratio of 36:12 over 44 innings of work. He's another Tommy John survivor, having had the surgery in 2013, at the tender age of 18.
The Braves get
Ender Inciarte was signed out of Venezuela in 2008, and made his major-league debut in 2013. The outfielder, who turned 25 in October, was able to command a regular spot in the line-up this year, and batted an impressive .303, mostly out of the D-backs leadoff spot, with an OPS+ of 101. His defense was excellent, contributing heavily to his 5.3 bWAR. Socrates Brito will likely be the main beneficiary of Inciarte's departure, joining A.J. Pollock and David Peralta, along with Yasmany Tomas, in the D-backs outfield. The question of who will replace Ender at the top of the D-backs order, remains to be answered.
Aaron Blair. A supplemental 1st-round pick by the DIamondbacks in 2013, Blair is a prospect whose stock has been steadily rising over the past couple of seasons, and he was widely considered to be a part of the team's rotation plans in 2016. Indeed, there was some surprise we never saw him in 2015, but instead, Blair split time between AA Mobile and AAA Reno, combining for a record 13-5 and an ERA of 2.92 - no mean feat, especially given the environment in Reno. He was a particular fan favorite on the 'Pit, not least because his father was a regular visitor here over the past year - and, naturally, stout defender of his son!
Dansby Swanson. The #1 overall pick in the 2015 June draft, shortstop Swanson only got to play 22 games in the Diamondbacks' organization before today's deal, playing for our Low-A affiliate in Hillsboro. He thus has a shot to become just the third #1 pick to reach the majors after being traded, following in the footsteps of Adrian Gonzalez, the Marlins' pick in 2000 who was dealt to the Rangers, and Shaun Abner in 1984, who went from the Mets to the Padres. For the Diamondbacks' sake, they will be hoping Swanson's future trajectory resembles the latter, with his -1.3 bWAR, than the former (41.8 bWAR and counting).
This was certainly an awful lot to give up: two of the three would have seemed like a more reasonable balance (or even, perhaps, swapping out De La Rosa for Blair), and the stark fact is that the D-backs are giving up almost complete control (17 years) of three players of undeniable potential, in exchange for three years of Shelby Miller and a guy who couldn't crack John Sickels' top 20 Braves prospects last month. Those who value prospects are, entirely predictably, eviscerating this trade, e.g. painting it as "proof that executives Dave Stewart and Tony La Russa are out of touch in the analytics game."
On the other hand, it's clear that the D-backs front office see their window of opportunity to win as right now, with All-Stars Paul Goldschmidt and A.J. Pollock spearheading an offense that, on 2015 performance, is still likely, even without Inciarte, to score more runs than just about anyone else in the National League. The problem last season was pitching, and starting pitching in particular. That no longer appears to be the case with, as noted above, a rotation that appears capable of going toe-to-toe with anyone, and possessing a 1-2-3 in Grienke, Corbin and Miller, that should serve the team well in October.
There are some deals, particularly those involving prospects, that can't begin to be accurately assessed for years. That doesn't appear the case here, particularly from the Arizona perspective. If Miller helps take the team to the post-season in the next three seasons, then the trade will have accomplished exactly what La Russa and Stewart intended. If there's a World Series trophy in there, whatever Swanson and Blair may do further down the road for the Braves really won't matter too much to Arizona fans. But if the playoffs don't happen, this will be a trade offering a lot of scope to repent at leisure.
It's clearly all-in for the Diamondbacks in 2016, and we can only commit to that process, and hope it all works out in the way that is clearly intended.