I guess I got it right based on the setlist
Her heavier single tracks aren't that big... t2m, decision, rule, Microphone... people out of her fanbase don't care/know about those songs... And she can't really face an audience made of people who aren't familiar to her work with stuff they just don't know and don't care about knowing. If those people aren't her fans, they were expecting her hits... Not some random unpopular single or obscure album tracks.
Also... rock =/= dark... Rock can be dark and edgy, but it's not like this is the only way of doing rock music... This was a festival celebrating the aniversary of the main band... People were there to celebrate, not to cry (or laught at over dramatic ayu :B)