Sivir's Ricochet and (non-existent) rune interaction

Preface: I know this is long and i know some of you can't or won't read it. Those that fall into that category need not bother telling me tl;dr.

I'd really like some feedback on how Sivir's Ricochet is coded. I understand that only the primary auto-attack can deliver on-hit effects. So, if the bouncing taking place doesn't have any on-hit effect interactions and it's damage is based upon the first target hit. Does that then mean that it is coded and handled as an ability after the initial target? If that's the case, why does it have no interaction with any of the Sorcery runes?

If it's not coded as an ability but as an attack (similar to Ruunan's Hurricane). Then that still doesn't explain why Summon Aery and Phase Rush don't work, since they function for both attacks and abilities. Nor does it explain why on-hit effects cannot be applied. Now, I understand that Sivir's kit is a bit dated which is likely why they couldn't work the skill originally to handle all that. But I don't understand how this one champions skill could be over-looked for functionality with the new system. Or why this wasn't changed back when the changes took place to her ultimate.

It seems like a good opportunity to create some variance in her builds. Increase the bonus AD scale on Q and allow it to crit. While also increasing its cooldown but allowing critical hits with it to refund some of the cooldown based on number of champions it crits on. This gives a clear path to build damage and crit while avoiding it's abuse for consistent wave clear. While also rewarding skillful playing. Then decrease the bonus ad scale on W and remove it's ability to crit. But allow for on-hit's and runes to interact with it (scale back the on-hit effects like you would the damage per bounce similarly to how Urgot utilizes them during Purge). By doing this you'd give players an incentive to build towards damage and crit for more burst and frequent use with Q. Or allow for attack speed and on-hit builds which will be more beneficial against a tank/bruiser team that's likely to have a lot of health. This would make you a bigger threat in team fights against tanky compositions. This would also encourage people to switch up whether to take Precision or Sorcery runes for a match. Precision benefits from higher base damage from Q-focused builds delivering on more direct damage. While Sorcery provides better sustained harassment during lane phase with Ricochet proccing Summon Aery (but then having that rune fall off on effectiveness late game comparatively to Precision).

Currently, you just build damage on her and hope you get peeled during team fights to spread your damage while also negating enemy minion pushes. It's a really boring playstyle for an ADC. These changes would at least allow for variance between games beyond whether or not you build an LDR or not. If Miss Fortune's Double Up and Make It Rain can utilize Sorcery runes while doing substantially more damage than Sivir's Ricochet. Then I think it's about time we give that to her in a balanced way.

Also; I'd really like to see her shield grant tenacity when blocking a targeted ability (like a Pantheon spear or Jax leap) and only grant mana when blocking a skillshot. This way during lane phase she can sustain her mana costs against harass. And in ganks/team fights choose to save the shield for when a tank/bruiser dives on her. Allowing skilled Sivir's to choose what's more important. Blocking the APC skillshot's health chunk or the Lee Sin's Dragon Rage. Normally even if you block Lee's ultimate you'd die. Since he'd slow you and beat you down afterwards. At least with this change his decreased effectiveness on slow against your passive/ultimate will give you a chance of escaping after negating the CC.