Hi and thanks for your requests. I can answer some of the right away.
1.It is a lot of limitation in these apps since they are very small and they cannot do everything and they should be more like a compliment t other clients. In the web client you can do much more including select dates. However, I will forward this for an answer of if possible to add.
2.Specify a storage location for different cameras. This have been up to discussion before and it will not be changed from how it works today. The system is designed for everything to be managed from the client interface. The intention is not for the user to go into the Library and change things manually since that will mess up the structure of the Library. If you want to copy or sort things differently there are other programs that do that.
3.If you have e specific recording you want to keep it can easily be downloaded to a safe place on the HD. The reason to not have this tag for non deletion is that it mess up the function for automatic deletion which keeps the recordings within a limit of time or available space on the HD. Then you also need a function to find tagged videos since you most likely after a while forgot them. So if it is an important recording download and store it on a safe place which you manage.