Thanks for the comments Timo. It's great to see that you read take in consideration what your users think. I do understand your reasons for not implementing widgets (actually already thought that something similar would be the reason).
Yeah, I was taking about the bar all the way in the top of the screen. I do get what you are saying.
I will post in the post you inked about the shortcuts. Thanks for the link.
Here are some screenshots of some apps that I believe have a nice UI. The majority is dedicated to writing and I think can somehow be adopted by a diary app (I'm not a programer tho).
As you might notice they tend to be somehow minimal. The essencial is in front the rest is hidden in the bar or in settings I think.
The interface tends to be divided into three "columns" in one you have the calendar, chronology etc for example, in the other the dates of the calendar with a preview (in a diary would work the same way) , and the last one is dedicated to writing with some minimal options like Bold, "add image", Italic etc in a small part of screen (bottom or up) One of the apps also put's a lot of options in the right side.
Anyways, I hope that this could give some ideias for the future if you decide to do some changes