Broken Base: Fans are divided over whether it was a good idea to tell Vega's story, since we already knew it from Mass Effect 3. While some thought it expanded on Vega, others simply pointed out that this anime could have been about a part of the canon we know little about, like Garrus' time on Omega in between the first and second games.
Fridge Brilliance: While Vega himself might see his choice as All for Nothing by the time of Mass Effect 3, with the Sadistic Choice being his bitterest memory, it may not have actually been that bad. The admirals note that, in addition to specific details on the Collectors, the data Vega retrieves contains technology that can be used to upgrade humanity's weaponry tech, ship tech, etc. Thus, there's a very real chance that Vega's saving Treeya was actually a major contributor to humanity's ability to hold back the Reaper onslaught despite being caught off-guard by the invasion. Furthermore, Vega is too emotionally invested in the failure to realize that it wasn't a complete waste, not to mention the lingering good of his choice doesn't become really obvious until after Shepard has their little "heart to heart" with Vega in the game.