The significant issue comes with DS TB, when you have to fill platoons and have far less options to fill those from when it comes to your roster. "Hey, fill these 6 platoons and then do these 4 missions!" That is fairly easy for LS TB side compared to DS TB because there are so many more LS toons. People can sacrifice much easier.
At the same time, I kind of roll my eyes at the "named character" thing because while yes, named characters are a big deal in Star Wars, there aren't only named characters in SWGOH. You also see named characters as NPCs that we can't play (i.e., Emno) that they could release for us to use to build the DS toon count.
More importantly, there are dozens of "named" dark side characters in Star Wars lore and since SWGOH is considered "legends" they could bring any/all of those characters to the game for us to employ. (i.e., Exar Kun, Plagueis, Bane, Malgus, etc etc etc.)