Most of all the key features of Iridium, I like its privacy and anonymity. Because by default with Iridium your transactions are not tracked, and the balance of your wallet is confidential.
So am I and I make a point of honor on this aspect : since v4, a tx with a mixin under 3 will not be accepted by the network.
Every idea developed for future or near improvements start by this question : is anonymity respected ?