The thing is Mr. Terrific completely fit into the JSA as a legacy character because his origin made so much sense - he was in the same situation (a man who had reached the peak of human abilities and was now contemplating suicide) as a man he had never met (Terry Sloane) but used the original Mr. Terrific's story to give meaning to his own life. It explained why Michael took on Terry's original cheesy slogan (Fair Play) and why he wore a "T" on his face (he was explicitly taking on a super-hero persona just as the original did). I had no idea what the rebooted Mr. Terrific's motivation was to be well...a guy who called himself "Mr.Terrific" and whatever reason the book did give it was never going to be as good as his previous one.

Just like with so many of the unnecessary costume changes (Mandarin collars for everyone, give Power Girl a "P" logo, have Superman wear armor, give "Shazam" a hood), the reboot of Mr. Terrific was just not as good as what DC discarded. You really get the sense that with the exception of the 4 Robins (which seem clearly a case of Editorial favoritism to me), the new DC despises even the idea of Legacy characters.