Panel Counts for ONK Characters
This quantitative analysis of ONK panel counts for the ten most commonly-drawn characters confirms my naive impressions. Aqua has 2812 panels, Ruby 2354, Kana 2243, Akane 1409, Memcho 781, Miyako 489, Ai 469, Gotanda 372, Melt 291, and Shiranui Frill 278. Aqua has the most panels, Ruby and Kana are not far behind and practically tied, and both have ~50% more then Akane and ~3x more than Memcho.
Notably, this is not in-line with their actual importance to the broader plot or characters; Kana (who is not only nowhere near Ruby's importance but nowhere near Akane's) either should have been much more important or gotten much less page-time; this reflects her prominence in the plot-tumor Aquabowl and her displacement of Ruby until the Private Arc.
Also reflects just how concentrated the cast is; ONK is very much not an ensemble story, it's Aqua + three major girls (Ruby, Kana, Akane) and a bunch of minor characters (with the arguable exception of Ai who is prominent out of line with her panel count). It's also very close to "Aqua and his harem"; the first non-Aqua man on the list is Gotanda at #8 with half Memcho's count. Ideally Taiki Himekawa would have been #5 on this list rather than not even present, and Kamiki would be on it too (need page count to do things beyond look intimidating and die). Anyways, Gotanda was robbed in the Finale arc of the emotional weight he should have had as Aqua's surrogate parent (given to Miyako instead). Boo!