New App vs Update

[OgreSwamp]

Hi,

At the moment my app generates stable (but low in digits) profit. It has 5 stars only reviews, but very few (7 or 8). App has 2 versions - full and light.

So for the new version I completely changed design, icon and added some features (not too much of them), so basically it is same app but with much better design and in-app purchases wil be added in few months.

could someone point me some pros/cons between new version of the app or creating a new one.
I understand that creating new app can make my current users unhappy. But I remember some apps (e.g. tweetie) did it.

May be someone has an experience in creating new app instead of updating current one?

BTW, app has some media content (like templates for drawing and music). New version will have same content + some extra templates.

Thanks!