While I agree with what you've said, I will add two more advantages the 2C has, one big, one small.
First, the bass impact on the 2C is outstanding for a planar, reaching into the level of a good dynamic driver. That's the reason I bought mine. Despite its quirks, the 2C really excels at the visceral feel of the bass. On the other hand, that bass is not as extended, detailed, or controlled as on the X, so there's a big trade-off there. You can also EQ the bass on the X to almost get to the sound of the 2C's bass, but, of course, EQ is not going to help the 2C achieve the better bass of the X.
Second, the 2C is easier to drive well. Out of a DAP or a small amp, it still sounds nearly as good. On TOTL gear, there is some improvement, but not enough to make you feel like you're missing out without it. The X is much more particular when it comes to smaller amps and scales considerably more. Worse, it's a bit unpredictable. On my DAP, the X sounds decent, but on my Black Label, with about three times the power, it doesn't. So, picking between the two headphones, you'll want to consider how you'll drive them.
