With Joomla 3 there really is no need to use K2 and now that there are tons of add ons that are just as good as K2 but bypass the styling. One of my "author friends" on Themeforest decided to make the same template with and without K2 and this way his customers had the best of both worlds. When you go to download his themes he would have a comment to let him know if you needed the K2 version.
On my part I have many, many clients and I had noticed that they did NOT LIKE or WANT K2. So on my end, thank you for not using K2 on all your themes. There are "very popular joomla clubs" who now incorporate K2 in almost 95% of their themes and their membership has not been the same ever since.
I went from 8 clubs per year to just one and that is Shape5. Why... no K2, Light and dark styled themes, Warmth & ease of use. I am happy