Permanent Gold Boost

I suggest instead invest in stat boost then you will kill higher monsters sooner and gain more gold AND EXP.
Or invest in exp bonus and you'll reach a higher tier sooner getting you to higher equipment that will in turn help you fight higher mobs bringing in more gold AND Exp.

I think gold is well balanced putting more gold into the game and making those that can afford to pay for credits richer isnt going to help any.
More gold in the game is only going to push up prices on the market.

I would like to clarify my points above.

Basicly, I disagree with putting more value to gold boost and am very against it. Which is why I pointed out the value of the other boosts. I am much the same as you (gold boost for me is my lowest investment.

My main point being... you are already getting so much gold boost from the other boost. Putting more value on Gold boost would nerf non paid players even more. More gold in the game economy is not the solution. There is already enough value in the boosts we have for people to want to purchase credits.
There is no war between the boosts, all players have the same information when they go into purchasing boosts. If it happens that they don't want to upgrade that boost until all thier other boosts are fully upgraded, then I don't think it is going to affect the game, or any sort of fairness that they are unbalanced, as you say.

Considering the cost to upgrade all the other boosts to full (even without 2500 credits required to fully upgrade gold bonus) is 23750 credits which is at a minimum $1772 value. I don't think it is a big issue considering only 6 people playing the game are beyond this point in renown.

My final point is that Stabzs puts alot of thought into the economics of the game to make sure the game economy doesnt suffer huge inflation (or deflation), in my opinion the game needs more gold sinks not more gold.