It would definitely cut way down on the number of suits, both frivolous and legitimate ones. I just don't want to see someone who rightfully brought a suit, but lost because they didn't have enough evidence, be punished.
Such a system may also create sort of a catch-22 on a psycological level. A jury, knowing how the system you propose works, could easily get a mindset of, "Well, the plantif surely wouldn't file such a suit if it wasn't true, considering he/she must pay is we find for the defendant". That wouldn't be good because a person who files such a suit(or the attorney who advised them to) could start thinking "well the jury would have to think I am an idiot to bring false charges considering I have to pay if I lose". I think it creates a potential psychological battle between a jury and the plantiff(and attorney). I may be wrong, but I don't always trust juries to be objective when looking at evidence.
I'm working on it!