As a kid, I always saw Mercury Aqua Rhapsody as stronger because the water she was summoning was different. The water in Shine Aqua Illusion looks more real/organic, like water you can find out in the real world, but the water in Aqua Rhapsody looks more mystical, so I always assumed it had special magic properties that made it stronger. Of course, they're both magic attacks, and I know that was just a headcanon I had as a kid, but I guess that's part of why Aqua Rhapsody seemed stronger to me. Also, she seemed to be summoning up a lot more water, so yeah.
omfgggg the inconsistency of Love and Beauty Shock bothers me to this day. Sometimes, it's a bolt of energy that just disperses once it hits something and sort of stuns its target (when it attacks that Phage with the keyboard). Sometimes, it's a rolling ball of energy that just smashes through its targets and does a lot of concussive damage (when it destroys JunJun's giant ball thing). Sometimes, it's a slicing energy ribbon thing (against Nehelenia's puppet dolls)? And sometimes, it's a small beam of energy (SuperS)... like, make up your minds omfgg. I love the sequence for Love and Beauty Shock; it's sooo cute and so unapologetically hyper-feminine, but the way the animators had it manifest in battle was so annoying.
Oak Evolution was lame, too. It just felt like a weaker version of Crescent Beam Shower to me lol.