I agree that your solution 2 or 3 would be interesting, but it involves a whole new game design, in order to correctly balance the cost vs. power for each card, which means a lot of beta testing and so on...
On the contrary, the modification I propose can be implemented in one line of code by the developpers, and I'm quite convinced that it would improve fun for players... But hey, I'm not the lead developper, so...
You are making this issue bigger than it is.
There is nothing wrong with Quantum Towers. They work perfectly when they give 3 random quantum. If they gave only 2, they would suck big time. And randomly choosing 2 or 3 is equally bad because card games already have too much luck involved and this would just add to that.
Problem is not Quantum Towers, problem is the other cards. There are way too many cheap awesome cards like Otyugh, Steal, etc. that rainbow decks can easily use. Like I said before, I think it sucks that most expensive cards like dragons only do damage and have no abilities.
Worst card at the moment is Sundial which has changed the entire game. 90% of decks in top-50 are rainbow and use Sundial. Why? Because Sundial keeps you safe early in the game when rainbow decks are most vulnerable. Also it lets you draw more cards which is another huge advantage to rainbow decks.
Here is my anti-Rainbow deck that is very simple yet it destroys any top-50 rainbow deck out there. All you need really is protected Pulverizer and you will win.
So you see rainbows can be beat, and there are already many decks that can do that. If they did a huge nerf on Quantum Towers, rainbow decks would probably become very weak.
What I would like to see is:
- Sundials last for only 1 turn
- Supernovas cost 3 quantum (maybe..)
- Bone Walls only get ONE extra layer when a creature dies
- Some OP cards made more expensive
- Most expensive cards in game made better (and maybe also 1-2 quantum more expensive)
- Use of upgraded Pulverizer cost 2 quantum
These changes would balance out the game pretty well I think.