Heck of a pile of money for an "entry level" camera body ....
Actually, the silly part, IMHO, is that being able to tell the camera body manually what lens aperture you're using, and let it pick a shutter speed, or provide some kind of match-needle style metering has to be about as simple a function as you could ask for. My old SPIIa could do that, as can the N6006, which isn't quite "entry level", but close.
Come to think of it, my circa 1972 Exacta could do that - I've still got a 500mm (Spiratone) tele (not a Cad) that uses two rings - one to stop the lens down for metering, and a second one to crank it back open for focusing. Ready to shoot, and you turn the second ring to the stop. Not quick, but way simpler than an automatic stopdown. The basic Exacta setup used a preset lens well - same idea, except that pressing the shutter button stopped the lens down, and you had to crank it back open.
No need to tell the body what aperture you're using. The meter is trying to hit a grey-scale point by looking at the light coming in, and comparing that with the shutter speed currently set. Letting it tell you to change the speed to get closer, or to automatically set one it likes, would be trivial.
Aperture-priority mode needs to be smart enough to just tell you if you hit a shutter speed it can't set - too fast, or too long.... Manual mode ought to just tell you that you've picked a shutter speed and aperture combo that is correct (without really knowing what the aperture is).
Now, I'm getting upset ....
(Well, not really.... Just kind of funny to find a "legacy" lens that will mount, but won't work at all without an external meter, given that the one in the camera is smarter than I am .)