Since Koei copied Toshiie's look from Capcom's Sengoku Basara, they might as well go all the way and plagiarize his moveset as well. Therefore, we can probably expect Toshiie to wield a spear or two and have a very fast moveset.
This is blatant sarcasm, except the last part. I have lost faith in Koei, especially since they could have created a unique look for Toshiie WITH EASE. Not only was Mr. Maeda a bad character choice, Koei also ruined him by failing to make him substantially different from Capcom's version of him. I truly expect Toshiie to have a totally bland moveset.
And I expect a woman. Just my opinion though.
They could add Matsu or Otsune since they're adding Toshiie. Methinks they could add another chick or warrior to the Tokugawa, though.