I mean the stats of the final evolutions of the starters are pretty good and they all have useful hidden abilities. Would you say this generation had the most powerful Starter Pokemon?
No. Currently, more Gen 1 starters are relevant in higher tiers, but historically, Gen 3 had the most useable starters, coming in at three. Gen 4 had Infernape, who was a top 15 staple in gen 4 and stayed in the high 20s in Gen 5.
Right now, Gen 6 has two OU viable starters, but I suspect Greninja is just a fad. He will not remain common once the novelty wears off. Chesnaught is the one most likely to find a niche in teams more often, but only slightly.
TLDR: Gen 1 and 3.
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