Omnistone Replacement - No Keystone: Balanced, Broken, or Weak

I don't think anyone is really that happy with Omnistone, I myself have never seen it picked in one of my ranked games. The rune meant to give you a taste of what every tree has to offer just ends up being a novelty at best in lane that that is simply too random to be useful in late game and has to few keystones that can proc in the jungle to make the rune really viable on anyone really.

I liked the idea of kleptomancy but it ended up just being a keystone that could be abused on a certain frew champions with on-hit affects to snowball the game hard and pretty much useless on anyone else. Similarly I like the idea of a Keystone that gives you the freedom to choose a bit of power from each tree but Omnistone just isn't the right implementation.

My idea for a better implementation of such a rune would be a rune that allows you to take any 6 minor runes regardless of tree, and possibly tier as well if that didn't make the rune too broken. Keystones are definitely the strongest single runes, but I could see quite a few instances where not being limited to the runes from 2 trees may be viable enough to replace not having a real keystone for instance:

1. A top laner that wants the survivability of Triumph, cc reduction of Legend: Tenacity, ult CDR of Ultimate Hunter, movement speed utility of Nimbus Cloak, lane help of Bone Plating, and maybe the utility of Time Warp Tonic.

2. A jungler who wants the clear speed gained from Legend: Alacrity, vision control from Zombie Ward, map presence from, Relentless Hunter, river control of Water Walking, a mini strength of ages via Overgrowth, and the powerspike of free boots via Magical Footwear.

3. A squishy support who wants the sustain of Taste of Blood, vision control of Ghost Poro, the item CDR of Ingenious Hunter, mana sustain from Manaflow Band, lane help of Second Wind, and the overall CDR of Cosmic Insight.

I think this would be least viable on mids who want the raw damage of a keystone or a adc who wants the late game scaling of a precision keystone but even then I don't think being able to pick up Nimbus Cloak + Timewarp Tonic in lieu of Phase Rush on a midlaner or Second Wind over Fleetfootwork would be that bad on an ADC. When paired with being able to take your remaining runes from any tree for instance the ADC in a bad matchup could get Second wind, boots, scaling from Waterwalking, AS from Legend: Alacrity, damage of Coup De Grace, and shield of Overheal. Or a midlaner can now have the freedom to take both manaflow band + presence of mind + biscuits without having to sacrifice what the domination tree has to offer allowing them to go straight into core items without having to first worry about mana.

**It may not be optimal for mid or ADC but I definitely think it would be better than anything Omnistone has to offer them currently. Additionally I think it could really be useful in certain scenarios in the other lanes with so many possible combinations that I just think its a better fit than Omnistone **

Like I mentioned above, the idea also has the potential to be expanded to any minor rune regardless of tier as well but I think this may be a little too broken. Bone Plating + Second Wind paired with Taste of Blood + Ravenous Hunter + Biscuits along with any rune of your choice would give even the weakest lane champion possibly too easy of a time at a point when the champion should be at their weakest. Additionally tier 3 of the Domination tree is considered one of the strongest, being able to take Ravenous + Relentless + Ultimate Hunter may be too much to not be broken on some champions. But hey maybe I'm wrong and keystones are so strong that the removal of this restriction would be necessary to make this a viable option on any champion.

Anyways what are your opinions on this?