>>718757852
Eh, not necessarily. If you remember the general time frame of the story, Force unleashed was pretty close to the beginning years of Vader's journey as he still had some jedi to hunt down
Plus, there was past lore of Vader losing many "mitachlorians" (unit of measure for force power) because of his body burning. He was also new-ish to the dark side at this time.
So yeah, a fully intact person with a lot of potential who he trained for years and who even ended up getting more training (Kota) would be a tough fight once things got going.