I don't know exactly what are the smooth transitions you refer. Everything is adjustable. You can set the length change speed (koofLen).
The Disable External Soft Views works as you said reverting to almost stock the behaviour, and was implemented like that by Storebror when he adapted the code by very first time for 4.12.
The way to get the real follow without inertia, is by setting this in Conf.ini (sabe your current values if you want to go back to them):
[MODs]
PAL3DFollowInertiaAngle=1
PAL3DFollowInertia=1
It will make instant (rigid) response to plane movement on where you see. Visual MOD essentially makes your point of view 100% relative to the actor. So with those values, the point of view gets "attached" to the position you fixed. The position itself is a 3DOF Spherical coordinate (Azimuth, Elevation, Length). The length is limited for each FOV. So if you want to get closer (over the plane), you should change the FOV, for example with what you tipically get in game with standard <Del> independent key of the keyboard which makes you go closer.
Then: so far being in a sphere close to the plane, but fixed and responding instantaneously to it, with the right mouse button and moving simultaneously the mouse, you point the camera wherever you want. So: if you maneuever the plane, the Camera will follow those movements pointing to the same relative point, being like "attached".
With a partial "attach" like the soft movements, it is interesting too, but it is true that it isn't like if the Camera was screwed to some part of the plane.
Regards,
Pablo