This is a very clever implementation, but it seems too strong because it provides so many buys and coins at little cost (just adding one mediocre card to your deck). For example, $20 and 1 buy becomes $32 and 16 buys.
I thought of that too. The benchmark here of course is paying the normal
for a Province, but you overpay first for a Logs. The end result is that you get a Log and a Province for
. But it scales pretty scarily indeed. In the situation you described, you go from double Province to quadruple Province. It is not nothing.
The idea is there. The most natural way to tweak the power level (after playtesting, of course) is to change the cost of Logs. It could be tried at
, for instance. The problem is that the initial barrier of usefulness becomes harder to cross. If you yield
in a turn, you're already doing good and Logs merely accelerate that good deck you've got going.
Edit: Here's a graph to better illustrate how the
and Buy correlate to the amount you paid for Logs.
As we can see, it takes $36 (no icons for that one I'm afraid) to pileout all 8 Provinces. Cool beans!