Cecile needed to really challenged every prosecution witness:
-Question DeVoe's wife about where she was at the time of his death.
-Ask for details about her new boy toy (also the jury just buying her story wholesale, and Cecile not having any real follow-up questions, was ridiculous).
-Maybe call Dominic to the stand and question him as well.
-Ask Captain Singh if a cop has ever planted evidence before (coughRalphcough), which opens up possible reasonable doubt.
-Ask if a metahuman has ever targeted the police before (the answer is yes). With all of the weird crap in this city, the idea that a metahuman with a grudge might frame Barry isn't that hard to buy.
-Bring up the fact that Barry is a CSI and wouldn't kill someone in such and obvious incriminating way.
-Ask why, if DaVoe was so scared of Barry as to get a restraining order against him, he decided to go alone to talk to Barry at night.
-Etc.
Instead, Cecile's entire defense basically amounted to "but Barry's a nice guy." Yeah because the women who's dating his friend/surrogate father figure/father-in-law, and is pregnant with the latter's child, wouldn't totally have a conflict of interest or anything, ugh.
Seriously I know people fresh out of law school who could have shredded this case to pieces. It would almost have been more believable to have the judge break the fourth wall and go "look, we all know that he's going to be convicted. It's only halfway through the season and we need to stretch this out, so why even bother making it even remotely plausible? Only the villains get to look even moderately intelligent right now, the rest of us are just dumb, really REALLY dumb."
Also there's no way that they'd send Barry to the general population. He's a former CSI who helped send at least some of those inmates to jail in the first place, and it was a high-profile case, you're just asking for him to get killed. He'd be in a separate wing, for his own protection.