I get where you're coming from, but the intent behind the changes are all wrong. The words are superficially nice, but the intent isn't. You know what they could have done? They could have reduced the area of effect on the auras and given them a visual update to clarify what they do. Hell, even an ugly thing like icons of swords, shields, and boots around the rim would have worked. Riot specifically went for destroying the basis of a substantial part of her mechanical uniqueness instead of the obvious, simple solution.
I don't get why you think sona's auras are very obvious. Sure, she has shiny circles beneath her, but most of the time I don't care. They're just kinda there. Having a visual marker isn't the same as being clear in how they work.
Plus, the auras have really tiny effects that aren't obvious at all. I don't plan on doing X when her aura is in the purple state and Y when it's green, eg.
Again, how is that different from half (or more) of the other passive buffs in the game? That aside, the argument being put forth by Riot is at least in part "people don't recognize that the buffs exist" rather than "people don't understand what the buffs affect", which is directly related to the visual indicators. I hate to be rude, but on the last point, duh? As above, they aren't something that the Sona's teammates need to react to, and they aren't something you use to set up initiations (like, say, Crescendo).
Also, "tiny"? Take a look at the gold value per stat point, based off of the cheapest items. At rank 5, the Q aura (+20AD and AP) is worth 1155 gold. The W aura (+10 Armor and MR) is worth 400 gold. The E aura (+20 movespeed) is worth 260 gold. Obviously the Q aura is most valuable in terms of gold efficiency equivalency, but situationally the W and E auras are also notable, the latter in particular as it makes it much easier to provide mobility to your whole team, especially when combined with the additional 12%+APratio.
A moderately important part of good Sona play is understanding auras and rotating properly for a given situation. It's plainly a case of a champion's abilities being dumbed down in favor of flashy visual effects and less differentiation from the kits of other champions; there's no other champ with the same sort of aura mechanics, but there are plenty that give shields, short-duration movespeed buffs, and on-hit effects. Yawn.