Minna and Mio also happen to get the only canon kiss shown in the anime, though it happens when Minna (if I recall right) is drunk. There's a fair amount of subtext I think coming from Minna's direction, so I would say it is one of the stronger pairings among the anime characters (trailing behind Eila x Sanya and Yoshika x Lynne, but not much else. Perrine has strong subtext towards Sakamoto as well but I prefer her with one of the non-anime characters, Amelie).
Also, Eila and Sanya technically received two focus episodes if you're considering both the first and second seasons. Although their season two episode is the stronger one I still consider the S1 episode very enjoyable.