Yeah, it's a nice idea.
I think it is quite situational though. Being only really valuable in a Trio (which is good in a way)
If I was running a trio, Gravity/Earth/Time with Fire as my mark (for Graviton Fire eaters), In the early game, I'm guessing this will pretty much have a 33/33/33% chance to give me either Gravity/Earth/Time. Presuming I have equal numbers of them in my deck. If I have Drawn/Played all of my Time Towers, I'm guessing it will have a 50/50 chance to give me Gravity/Earth presuming I have equal numbers of those towers in my deck. And, likewise, if I have played all my Gravity towers and have only Earth left in my Deck, every turn it will give me an Earth quanta until I have drawn that pillar - then it becomes redundant? See Mafidufa's point above.
It is situational in that it is pretty much useless in a Duo deck. You wouldn't want to put 6 of these (slowing the offence/pace/speed of your deck completely) in a Duo. You would much rather increase the ratio of Pillars to Other cards.
Again, it loses all 'usefulness' in a Mono deck. Since it will pretty much function as a Pillar which takes up an additional Permanent Slot and loses it's ability to produce quanta when you have played all your Pillars.
I like this one. If newbie guy put a Soul pillar in his duo deck he would understand what it could be used for by trying it out. So this passes my Simplicity Test [TM].
A minor problem. But, my only problem is that, would a 'newbie guy' bother to buy this pillar or even know about it/where to find it in the Bazaar? The Bazaar is pretty confusing at the best of times and with the sheer amount of cards being suggested daily, it can only get more so.