But, anyway, head-canon.
I think the original design for the Ambassador Class, that didn't make it to "Yesterday's Enterprise", is an intermediate design between the Enterprise-C and the Galaxy Class.
If Starfleet hadn't decided to not have an Enterprise for 20 years out of respect for the Enterprise-C being lost with all hands (another piece of head-canon, which I strongly agree with), I think original concept for the Ambassador Class is what the Enterprise-D would've looked like. If it had been launched in the 2345-2349 range.
It just looks like perfect design to come in-between.
I think the original design for the Ambassador Class, that didn't make it to "Yesterday's Enterprise", is an intermediate design between the Enterprise-C and the Galaxy Class.
If Starfleet hadn't decided to not have an Enterprise for 20 years out of respect for the Enterprise-C being lost with all hands (another piece of head-canon, which I strongly agree with), I think original concept for the Ambassador Class is what the Enterprise-D would've looked like. If it had been launched in the 2345-2349 range.
Designing the Enterprise-C — Forgotten Trek
Rick Sternbach created the 'C' in just a few days, using Andrew Probert's design as a stepping stone.
forgottentrek.com
It just looks like perfect design to come in-between.