Completely agree. The two biggest factors for me are SCO performance and Yaw rate.
Most of the old ships have very low Yaw rate compared to their Pitch, which apparently was an early design decision where they didn't want to have "turrets in space". Some of the new ships go completely against this. Interestingly they didn't do it with the Python Mk II, but the Mandalay and Cobra have massively increased Yaw compared to comparable ships.
This table is for similar builds/specs. The green bar in each column is how it compares to all other ships in the game.
Comparing the Krait Phantom, the previous (arguably) 'best exploration ship', with the Mandalay...
They have similar Pitch and Roll values, but the Yaw rates are very different. The Phantom was one of the lowest Yaw rates in the game at 17°/s, whereas Mandalay is now one of the highest at 46°/s. The Mandalay is also much closer to 1:1 Pitch to Yaw rate.
Cobra Mk V vs Cobra Mk III is a similar story, plus Pitch and Roll are 16% and 21% greater respectively. Yaw itself is 3.25x greater, or 225%...which is crazy.
Interestingly they didn't do this with the Python Mk II, but it
does have around 20% greater Pitch and Yaw than similar sized ships, whilst Roll is almost the same.
For me, this basically means that the Phantom is obsolete. If I'm out gathering I'm going to take the Mandalay as it can manoeuvre much more easily with Yaw on a planet surface when hunting brain trees, and SCO performance means that it's way better for anything related to Supercruise travel, like hunting down HGEs or reaching points-of-interest in general exploration. I love the Phantom, but practicality wins out and it's now useless :/
If the Corsair is also closer to 1:1 Pitch vs Yaw then that will put a spanner in the works for medium ships. Will I ever want to take out anything else for combat?
I can see them fixing the SCO problem, but will they be able to address the Yaw imbalance that they are now introducing with the new ships?