1st Gen
Competitive - ???
Avergae - ???
Dud - ???
See, I get problems here already. Charizard is hardly a battle master, but it's overhyped alot. Venusaur is a beast to take down, but it's alot less populair , and not overused at all. Blastoise just plain sucks, but has ALOT of fans, who hardly consider it a dud
2nd Gen
Competitive - Typlosion
Average - Feraligatr
Dud - Meganium
This one is easy. Ever since Typhlosion got eruption, it's been like a 2nd Charizard. And to be honest, it is pretty good. Still, not as much of a competitive 'beast' as more standard sweepers, but by far the most common Johto starter. Feraligator is an okay Dragon Dancer, and a suberb Swords Dancer, but is generally overlooked and it's not exactly top OU. Meganium sucks, and everybody knows it.
Don't know why really, just seems right.
3rd Gen
Competitive - Swampert
Average - Sceptile
Dud - ???
Blaziken? a Dud? Well no, not really, but it's definatly the worst one in Competitive play. To call it a dud is hardly accurate howeverm seeing as it, like many other fire starters, has a huge fanbase. Swampert, on the other hand, is not populair, but it's overused as hell and praised for it's competitive excelency. And Sceptile, what can I say, it's, but Swampert is much better at what it does.
4th Gen
Competitive - Infernape
Average - ???
Dud - ???
Infernape is an overhyped, overused Pokemon and it damn right deserves to be, since it tears through teams and every set is almost equally effective. However, both Torterra and Empoleon are excelent choices for competitive battling, but both are not nearly as overused as Infernape. in fact, they are severly underrated, but I don't think anyway refers to them as "duds"
I tried. I really did, but your descriptions are flawed ;/