You are overrating Ness' ground game, it really isn't that good. I said it was below-average, not sh*t (look at Jigglypuff's for sh*t, probably the only good thing about her ground game is DAC and dash attack besides her grab game).
Usmash has decent range, the charge can mindgame/punish shields and spotdodges, and it pops them in the air but it lacks priority and kill power.
Ftilt has decent knockback and priority and has nice speed, but lacks range.
Utilt can combo into itself a couple times at 0% and effectively pops up opponents in the air, it has nice vertical priority/range but zero horizontal range. Plus it kills earlier than usmash.
Fsmash is too slow. It has decent range and nice kill power, but that means nothing if an opponent can see it coming and defend against it.
Jab would be better if it had more hitstun for things like jab cancels and being able to land the 3rd hit. Dsmash is bad, the charge never leads into the strong hit and many characters avoid the strong hit due to poor design on the dsmash. Only good if facing a character that can get hit by the strong hit.
Dtilt is almost useless. Very little range and zero hitstun means it can't trap people and people can easily shield and counter. Only use is if it manages to trip the opponent.
Basically most of his ground moves have at least one or two good qualities, but a lot of bad qualities. But we are getting off topic, this is a power ranking thread and not a move discussion thread. So I am done.