I too would like to join the list of users that are unhappy with the idea of having to pony up more for an app we already paid for. I don't mind paying more to the developer for more features but a skin is hardly a new feature. (btw, many other apps allow for extra features without charge and many don't even charge for major overhauls).
This is especially frustrating with the debacle that 4.7 when I upgraded from 4.6. I am much more forgiving with apps that are on a donation basis (I usually, like in this case, pay a donation) vs. apps that force to pay. When I am forced to pay, I expect higher quality, better support, etc.
A side note, I know myself and a few other users would love to use their SD card to save their music on but get a "invalid cache location" error when attempting to use the sd card as a cache location. This is actually an Android issue and if done the way google says so, it will result in this error. Samsung is aware of the issue so they provided a work around (http://www.chainfire.eu/articles/113/Is ... SD_cards_/). If this was added to the upgrade, I would buy it because of its extra feature, but of course that is because I have a Galaxy S3....
To sum up, unless the direction of pay-to-play in conjunction with the myriad of issues is changed to either a higher quality with the pay or back to a donation basis, I will be looking for alternatives. I would love to see an explanation of what and why it happened.