One quick question. Instead of a lincese fee, why don't you open a pool and make mining there mandatory, you can then collect a percentage of the overall mined coins. Seems fairer and also easier to control for me.
1) One pool controlling 90%+ of the "hash" power is very bad for the coin. This was the biggest concern.
2) We wouldn't be able to prove that we're getting 5% or 10% for ourselves and not 30%-50%.
3) It's much harder to code and to maintain. It would have probably took us additional month or two before release. With the price of XPM declining so fast it was very risky.
4) We would've needed to get rid of the encapsulation of the miner into the server and an open-source client and put everything into signle closed-soruce executable. As a result - more "fishing alerts" from botnet owners.