Even though she was gone for three whole years, not a single person left Vert's guild in 4 Goddesses Online.
An event in the game has Histoire and Nepgear worried that Neptune is actaully doing a lot of work since she would usually try to avoid it. Nepgear goes to see if Neptune is okay and she is. The reason that Neptune is working so hard is because she knows she isn't the best CPU big sister role model to Nepgear and thought if things didn't change, Nepgear would come to hate her. Nepgear states she could never hate Neptune, which Neptune knew, but the thought still scared her. Nepgear states that a diligent sister is nice, but that she likes her sister who thinks that playing with her is the most important duty of all. She then help Neptune with her work so that they can play together sooner.
One of Uni's bonus voices has her outright confess her love for Nepgear. This is never done in game, but it's nice to see her admit it outright.