Phoenix Wright: Ace Attorney: Trials and Tribulations - Traces of Distant Beauty Remix

Personally, when it comes to ranking Dahlia as an "Ace Attorney" villain in regards to her threat level and degree of evilness, while she's a psychotic manipulator with a body count, she's small-time when you compare her to other villains in the series for one reason: her inability to plan.
Sure, Dahlia could come up with schemes to get what she wanted, but all of them heavily relied on her using her looks and charms to recruit accomplices and/or attempting to get out of trouble, which is why they always quickly took a turn for the worst when someone didn't fall for her tricks, such as Mia and Diego. Heck, the majority of Dahlia's schemes were her trying to cover her tracks after her first botched scheme.
Don't get me wrong; I have nothing against Dahlia as a character since she did a great job showing how Phoenix went from being the sniveling little mess of a simp that we saw in "Turnabout Memories" who did nothing but cause trouble for Mia to a confident, competent attorney who was worthy of continuing his mentors legacy. However, I wouldn't go as far as putting Dahlia in the same bracket of villainy as the likes of Blaise Debeste, Matt Engarde, and Ga'ran who not only did their nefarious deeds to accomplish a goal, but because they loved every second of it.