@Ryus
I was talking about old Miria too, obviously you haven't read my reply with enough attention. It's been explicitly stated that
Miria's new phantom is SLOWER than her old one where she relied on youki bursts. So it doesn't matter she has become stronger and faster overall because with Riful she was only running away and disappearing, i.e. she would do at least as good 7 years ago if it only meant running away, at least for a short distance. Still it would be much better than what Renee did, where she couldn't even escape
Riful in her human form and couldn't dodge her attack even though she was supposed to be an eye (thus she should have more of a time advantage than Miria). Miria on the other hand managed to climb up on Riful's head/
/whatever instantly and she didn't react. I doubt that Miria could do her mirage in the air so she had to climb up and she appeared before Riful's eyes so Riful should have seen and/or feel/sense her. And even though she had much longer reach than in her human form she didn't manage to stop Miria.
As for Miria only keeping up with Riguald who was slower than Isley - it's irrelevant. Riful had problems with dodging AFs in her human form and even though she had quite of a time advantage (she saw Alicia going at her) she wasn't fast enough to dodge her attack. She also couldn't hit her, even though she was using simultaneous attacks which just shows how difficult it is for her to deal with small opponents. Her ribbon attacks aren't that fast and the main advantage - spread attack is nullified if her opponent is very fast and small. Also notice that
we've never seen awakened Riful moving from her spot during the fight. The one time we've seen her escape wouldn't help her go after Miria since all she could do was to bounce off (and I doubt she could be very accurate, whereas Miria could change directions easily).
Well, before she met Audrey we've seen her moving but for some reason she didn't move when she fought Alicia... For her to catch Miria she would have to be in her human form and still it would take her more time than it took her to catch Renee who couldn't even dodge her ribbon attack and even though she was so confident with her legs her first reaction was to draw her sword (i.e. she was overconfident and would be pwned by Riguald like Flora was).