Wartime carrier-attack payloads near the practical ceiling

Were proposed 4,000-pound and 8,000-pound loads near the limit for wartime dive and torpedo bombers?

Yes; both figures were approaching the upper limits for those aircraft roles.

The question compares very large payload figures proposed for advanced carrier attack aircraft. Both figures reach the upper limits for their respective dive- and torpedo-bomber roles. They provide a scale check on designs that otherwise look plausible only as numbers on paper. Payload growth was already pushing these specialised aircraft toward the edge of their practical category.