Yeah, I didnt list Rajini's 70's movies. It was a general response.
Some performances of Rajni in 70's Bachchan cannot manage in another 7 jenmams:
1. thappu thALangaL
2. avargaL/mUndru mudichu
3. 16 V
4. Above all, muLLum malarum.
And that's not exhaustive. Just look at the versatility, the variety, and not just width but depth in each of these. Compare that with the single note (intense young man) of Amitji in 70's.
I mean, it is a no contest in Rajini's favour.