Porygon 2 - double grass move!
Answers
Correction, base attack is 198. So, maybe not quite as powerful as Exeggutor, but definitely usable to fill out a grass lineup. The Porygon will hit about as hard as Victreebell and Vileplume, but will be tankier. And he will not have the typical weaknesses of grass/poison/psychic types.
STAB matters less than type effectiveness now, so, yeah, I think this is a good and interesting mon.
Yeah, I probably looked at Porygon's stats, the point still stands, if you were to use him against a vaporeon, you'd be better off using charge beam (I'd have to calculate SE damage and I don't want to), even then Vileplume and Victribell deal a lot more damage (take less time to take it out), and resist his attacks, so I'm not quite sure he'd be tankier.
The question wasn't whether or not he should TM it to charge beam. The question was does it have usefulness as a grass attacker, and the answer is yes.
If you're going to cherrypick defenders, yes, Victreebell will be a little better against Vaporeon. The Porygon2 will be better against Slowking. But again, that wasn't his question.