Ness is low tier for two reason in my opinion.
Predictable recovery for one.
CGs and grab releases...
However, it doesn't really mean that ness truly sucks, it just means that sakurai clearly wasn't thinking right when he made ness. I mean, if there was a true counter to grabs in brawl, and ness had another option of recovering such as a pk magnet that can stall like fox's shine, ness would definitely deserve a higher ranking in the tier bracket...
I'll always main him no matter what though, hopefully waiting for a mysterious answer for his main problem, which is cgs. and when that answer is found, ohh boy, its on....