I am sorry but I think everybody is wrong.
I just tested both games just now and made a table. See below.
I use T300RS wheel and TH8A H-shifter. I don't use gamepad, so maybe it is different for gamepad users.
Testing options for Dirt Rally 2.0 are 'H-shifter with clutch or Sequential' and 'Clutch override' on or off
Testing options for EA WRC is sequential for VW Polo and H-pattern for Lancia 037 and 'Clutch manual' or 'Manual override'. (since there's no 'H-shifter with clutch or Sequential' in EA WRC)
You can see for seq-shifter cars, 'Manual override' for both games works like automatic clutch but you can still use clutch (for clutch kick or something)
but in 'manual clutch' you can't use clutch in DR2(maybe the car doesn't have one?? I don't know)
For H-shifter cars, 'Manual clutch' for both games works like real manual clutch,
but in 'Manual override' it works like 'automatic clutch' in EA WRC.
In DR1, there is an explanation for each options and for Clutch override it says like 'enables clutch working for cars even without clutch (for clutch kick)'.
I think if it is what the developer intended, DR1, DR2 was right, and EA WRC is quite wrong.
(first of all, thanks for bothering to check all those relevant combinations on wheel)
"For H-shifter cars, 'Manual clutch' for both games works like real manual clutch,
but in 'Manual override' it works like 'automatic clutch' in EA WRC."
This was the exact situation I described, but you probably missed that you can still temporarily override the auto clutch assist with what you have assigned for clutch only when Manual Override is enabled (vs. Automatic Clutch), which is a main differentiating aspect to Automatic Clutch. And yes, I can only mention gamepad usage for DR1/2/WRC set as manual sequential+clutch override, where it acts the same on all games, regardless if the car is seq or H.
Anyway, part of the mismatching behavior you observe could be related to WRC not even offering the "H-shifter with clutch or Sequential" option (for users with both paddles and H+clutch mapped), so paddles or H will only work depending on the real chosen car setup instead of overriding all cars. So that would also affect Manual Override behavior depending on real car transmission.
