ABSOULUTELY. Starkiller is an almost integral part of the Star Wars lore! The Force Unleashed explains the actual genesis of the Rebel Alliance, pointing out that Vader basically created the Alliance as a tool to kill the Emperor, using Starkiller as an agent to do this. Not only that, but too many things happened that cannot be just explained away by some Disney bullshit, between things like the sacking of Kashyyyk and the Prototype Death Star battle.
Besides, how awesome would it be to see both of Anakin's apprentices fight?
But if only you could see them
You would know from their faces
There were kings and queens
Followed by princes and princesses
There were future power people
Throwing love to the loveless
Shining a light 'cause they wanted it seen...