Actually, on a CO plane the number of seats in both configurations is 216. The current config is 27 rows of 31" pitch, 9 abreast. Switching to 34" pitch would leave about 24 rows (note that I am not taking into account the issues of lav/exit door locations or curvature at the rear, but it should be close enough). 24*9 = 216. Or keep the 27 rows and go 8 across and you get the same 216.

CO, of course picks the best of both worlds (for them) and puts 235 seats in the plane.

I may be in the minority here, but at 5' 11"/~190lbs I am just fine in CO's Y seat. Sure, I prefer J, but the Y seat doesn't kill me. I've done EWR-DEL and back just fine. Of course, I don't mind the 752 to Europe either, so I must be crazy

At the end of the day, I don't expect that the new lighting, windows or humidity are going to make the seat feel any more spacious, but that doesn't mean the flight will necessarily be uncomfortable.