That doesn't stop Toxrill, the Corrosive from being a very versatile commander even in competitive settings, a very popular 99er, and able to make some forays into Pioneer and Standard
Saruman the White Saruman the White can amass a good number of orcs if youre playing a spell slinger deck, especially if youre casting spells on other players turns as well as your own
This is solid by itself, but he is also not too vulnerable to spot removal because every time you play a vampire spell, you create a 1/1 vampire
Thrummingbird Thrummingbird is cheap to play, so it doesn't come with much punching power
Shilgengar's famine once starved Stensia into embracing vampirism
The option to run a Partner Commander is also a big positive, as is the wonderful thematic storytelling that went into its design