@Alex I re-ran the tests for you using the same saves, same layouts, identical everything vs. the same Ordo and Jangala station, but setting shield efficiency to 0.8, top speed to 35 and removing the missile hardpoints rotate flag.
I ran the Ordo fight twice. The result was 1 win losing 2 Pegasi and 1 loss. With a lower top speed, the Pegasi seemed to be more vulnerable to being surrounded by Remnants, resulting in death. This compares to clean victories earlier.

I ran the Jangala station fight three times (plus one that ended in a freeze due to Intel IRIS bug, which seemed to be heading to a loss since a Pegasus had gone down early). The result was 2 wins with no losses - but taking damage, unlike previously, and 1 loss.
In addition the character of the fights has changed. The Pegasus is no longer an agile and aggressive combatant but a slow lumbering battleship that takes its time to approach the target.
So, you have successfully nerfed the Pegasus and it is clearly no longer as strong as before.
Based on these tests I would keep it at 50 DP, not 60 DP. This is because at the 60 DP price point we have Paragon and Radiant which would have no trouble with these fights. I would also not nerf it further since three strong capitals really should be able to fight a Star Fortress and five strong capitals really should be able to fight an Ordo. However, if a balancing lever is needed, the next step might be to touch the armor or move shield efficiency to 1.0. Personally I would like to see you keep it as it is ie. 4 large missiles, .8 shield, 35 top speed for maybe one version's time and collect more data.