The loss of Gideon Emery was especially jarring. Easily one of my favorite voice actors in the industry, especially for his role as Balthier in FFXII, Gideon's inclusion in A Realm Reborn was fantastic. Though his role as Urainger was quite minimal compared to the other Scions, he overshadowed many of their performances.
...which leads to why I'm mostly happy the VA's were changed. The new cast does a real fantastic job of playing out the (much improved) story of Heavensward. They are, in my opinion, well matched to Gideon's talents, which makes me even more saddened he wasn't brought back.