I agree with the OP. I think it's the angle of the front windshield that makes the profile of the 2dr jeep look a bit off, especially compared to a TJ. The extra length of a 4 door offsets that angle a bit. That being said, it wouldn't be enough stop me from getting a 2dr if I wanted one.
The JL is almost spot on proportionally to the JK - JL is 1.4" longer in wheelbase(96.8 vs 95.4) and 2.5" (166.8 vs 164.3) overall.
Now compared to a TJ there is more of a change - 3.5" longer wheelbase and 12" in length. If I did my math right the JL length would be around 160 vs 166 to be proportional in length to the TJ, given it's 3.5" longer WB. Okay enough math in public and yes I am bored today to spend this much time on this.