As the artist explains, that definitely isn't the original Saber-class design. Which is why ours doesn't look like that one. However, I do like what he did to make the ship more consistent with other class design lineages. Specifically, the nacelle mounting ala Defiant. As both designs were developed by Starfleet at the same time and for the same reason: repelling a future Borg invasion.
It looks good from the front but I'm not a fan of the other angles. Super curvy space ships aren't my thing I guess.
The Somraw, K'tinga, D'Kyr, D7, Kumari, Xindi carrier, Xindi escort, and the T'Varo are all older than the Constitution Refit and yet they are tier 5. The Constellation is made up primarily of Connie refit parts and it is tier 5, there is no logical reason whatsoever for the no tier 5/6 connie rule.
(...) As both designs were developed by Starfleet at the same time and for the same reason: repelling a future Borg invasion.
Sorry, but not every ship was designed to fight the Borg and this claim has to be rooted out once and for all. The Defiant was the *one and only* ship this was stated about. All the other ships were regular Starfleet cruisers, the Sabre being a light cruiser, possibly a Miranda replacement, maybe at best it was a frigate to replace the New Orleans (or complement the line-up of frigates). It's no "battleship" either, despite STO classifying it as an escort, it's armament from the sources we got was rather in-line with every other ship class.
In fact, the Akira, Sabre, Steamrunner and Norway classes are strange animals. Their only purpose was to look "old" compared to the Sovereign that was introduced in FC, so it's not easy to determine where they were supposed to be logically in-universe. The Akira is a Heavy Cruiser (no, it's neither a carrier nor a torpedo boat of doom, it's a heavy ship with a lot of volume but average armament like all the others had as well. That's what the TM states and the on-screen canon supports that as it was not shown to feature anything that would make it stand out) and possibly serves alongside the Ambassador class to a certain degree. The Steamrunner is my prime candidate for a TNG-era Miranda class, though it is very similiar to the Sabre though the latter probably can be counted as a frigate so it's more closely related to the New Orleans and borrowed some traits from the Defiant visually, I give you that. The Norway is pretty much an Intrepid in dimensions and I'd suspect specifications as well. In the end, though, all of them were throwaway models.