EWR-BOM will be on a pmCO 772, all of which are equipped with lie-flat seats and are superior to LH's business class seats by a wide margin. I haven't done a flight quite as long as EWR-BOM on the 772 but I have flown IAH-NRT (14 hours) on that bird as well as on other TATLs and I find them to be just fine.

I'm a little confused by your post, are you talking about the difference between buying a business ticket and upgrading a coach ticket with miles?

I'll be flying to BOM later this year as well but I don't think it'll be in business class.