Just my two cents on one facet of this topic: Since the Valiant was destroyed, and the creators of the Valiant design models were working on a design for a ship very much still in service, isn't that more likely to suggest that they weren't
trying to depict the original Valiant's design? If anything they might have imagined the ship was named after the earlier Valiant, or as mentioned were just using a fairly generic name for a script that wasn't fully developed yet. The use of the name doesn't really strongly suggest at all that the Valiant was
Still like the idea, though, I just feel it necessary to point out possible issues. I'm enjoying this idea mostly because I get tired of Starfleet designs from the TOS and TMP era being essentially kitbashes of the Enterprise components. I like the idea of there being another distinct design era that preceded the Constitution-class, and that this era didn't necessarily look more "primitive", just different because of the practical necessities of technology at the time.