Like I said not busting chops just a change in prospective for me personally. I have no quams with the tsx, I support it in fact. On deer not required JMO but it certainly does the job.
In regards to penetration a heavier bullet will retain more energy allowing it to penetrate at further distances as well. In a cup and core or bonded style bullet it maybe be worth noting. In terms of a solid copper I agree dropping grain size does not limit penetration. I have achieved awesome results from the tsx on game much larger then a deer using the lighter/faster thought process.
FWIW I punch paper only to hunt big game. I don't consider myself a long range shooter in the least but will not hesitate if the situation is right to take a longer then average shot either.
Boils down to personal and gun preference. Confidence starts on paper, once tried/tested in the field it grows 10 folds.