I gonna answer them by gen k
Gen1-Squirtle:in gen 1 I always don't pic water type starter because there're other good water type out their like Vaporeon,Poliwag line and Lapras even if it's low level by no big deal so no water starter for gen 1 and the reason I don't hate Pikachu is I use him quite a lot in game actually when I fight againt Blue or whatever his name is I finish his last mon with Pikachu and it's always satisfy when I finish the game with my starter
Gen2-Chicorita:no need to say anything everyone know that Chicorita can't do any good in GSC or even HGSS I didn't mean it's not good Chicorita can fight and can be with you till you fight Red like Glitch did but Cyndaquill and Tootodile is so much better
Gen3-Treeko:I don't hate Treeko well actually Treeko is my favorite starter from Gen3 but he's the weakest out of all 3 starter,Torchic,Mudkip=2 typed and have good move,Treeko=1 typed and most of the move is grass type
Gen4-Piplup:I never finish Gen4 game before but from what I can see and hear people talking about these game Chimchar look dump and same type as Torchic but it can be powerful at the final part of the game,Turtwig is grass,grass is weak but when he become ground type he become a beast,Piplub...water/steel it's not a good type more weakness and it's move is not that good at all like the only steel type move that it can learn is Steel Wings and it can learn some flying type move which is not necessary at all there're Powerful Starapter out there that better have better move that Piplup move,I don't hate Piplup,he's cute and cute enough to be Dawn partner but he's SUCK!
Gen5-Snivy:look cool doen't mean it's good as most of people don't like Tepic more but he's still useful as an attacker even if he's slow but Snivy is a tanker and debuffer which isn't my play style,coil to make it tanker andheal over and over again by sucker other mon hp isn't bad but it's boring(for me)
Gen6-Fennekin:I like Fox.I like Fennekin and a lot too but when it's evolve it's not good even with powerful move most of it Psychic move is unnecessary because there're other good psychic type out there that can make psychic move damage better,Chespin is also bad but not useless I seen him in online battle sometime but Dephox,well I'm sure some people play online battle with it too but not much