Re: Hand of Nod (opinion!)
Snipers for GDI goes back to Tiberium Wars, where GDI was given Snipers as an advanced infantry. They're a reasonable addition to GDI flavor - much more expensive/higher tech level than Flames, slower at killing infantry, but of course long range. It makes some sense.
That said if there had been a thematic redesign of the factions from the top, snipers would fit much better with Nod's modus operandi, alongside flames. Generally speaking, as a whole, I always felt that Nod was/should have been mildly themed/balanced towards dealing with infantry, whereas GDI was/should have been mildly balanced against vehicles.