You've gotta remember that a Quantum Pillar is equal to three normal elemental pillars. And a Quantum tower is equal to two Quantum Pillars, or six normal elemental pillars or three normal elemental Towers.
And, with that being said, simply because a creature or card is 'colorless' (ie, uses random quanta) - by making it cost 3x as much as usual is not an excuse for it to be extremely overpowered. People often see a new idea which draws on random quanta and immediately they think of the cost, its ability, whether they would use it, or if it is too overpowered.
I'm sitting on the fence in the way Quantum (random) is used. Firstly, there are far too few colorless cards to know for sure. Secondly, maybe they are designed to be played quickly, perhaps that is the main idea behind 'colorless' (random) element cards.
So, for me personally, I think that is the way I want to see "Other" cards which are suggested. Low cost, can be played quickly, relatively expendable.
My reasoning behind this is, for example; "Other" cards can be mechanical or inanimate and it will take relatively little Quanta (of any kind) to make them work as they are supposed to. Whereas, to summon a Crimson Dragon (pure embodiment of fire) or a Mind Flayer (Waters ability destroyer) cost a lot more in terms of creating and sustaining them.
So, having said that, it is personally my opinion that Quanta or "Other" cards are kept simple damage dealers with mundane abilities and effects, but cost relatively little. Take for example Shards, they provide a once off +20hp bonus (Divinity) or a +5hp heal every turn (Gratitude). They also cost 2 and 3 quanta respectively, meaning they can be played on the first turn (Quantum Tower) or the second (Quantum Pillar).