At first I was thinking "Dominion Minions" as a title for the thread, but it's a pretty bad pun so I decided against it .
So, as promised, here are Vortas and Jem'Hadars. I tried to make them rather balanced (resp 12. and 13/14 picks), but as genetically engineered races, there is of course a few things they're very good at ... and a few things they're pretty ill suited for.
That said, I tried to create them so that it would also be possible for a PC to play one, for instance in a post-dominion war campaign. IMbnmsHO, if roleplayed well, such a character could lead to very interesting roleplaying sessions, with their Belief being questioned, their purpose in life, and so on.
A small seed for instance: The Jem'Hadars are a genetically engineered race, created for the sole purpose of fighting for the Dominion. If the Dominion, under Odo's influence, becomes more peaceful, the Jem'Hadars would not be needed anymore. But one can't (or can, for that matter) argue that the Jem'Hadar are a unique specie and have a culture of their own. Do the Founders have the right to decide the future of this race? Wouldn't be stopping their production in the cloning facilities a bit akin to genocide? Well, those are just a few ideas that could be used for a campaign in de Gamma Quadrant .
Anyhow, here are the races: