Very good question. I think we will probably make that one of the reach goals during kickstarter campaign. What other options do we need to look at?
replaceable cable - should be standard for any iems priced over $200.
volume control/mic - if you are marketing a consumer friendly device, you need to have this option available. It is such a hassle to remove the earphones and disconnect the plug to answer a call on the go. A mic on the cable at the very least.
carrying case - included with earphones.
chin slider - one that actually works.
minimilist style - solid silver, black, or white cable.