I haven't looked at newsletters functionality for a while and coming back to it after a few months I finding that's it's a little unclear what various parts are all about. Here's my first impression after not having looked at it for quite a long time:
Statistics: Clear and obvious, nothing needed here
Clear what it does but not clear that you should look at other things first. E.g. Really you should look at the templates tab, specifically the "mail templates" and set that/those up as you want first.
Lists is such a general term it's easy for someone to be confused here. Some text at the top of the page that says something like:
"Each of items in the list below will be a list that a subscriber can subscribe to." -- now see, list is being used for two different things and subscribe is being used twice so even trying to describe it is hard to remove potential confusion.
Perhaps rename the Tab to "Newsletters for Subscriber" or perhaps something more explanatory like:
"You can setup many types of newsletters for your subscribers. E.g. a "monthly" newsletter, a "Specials" and so on. Each one you create here will show up on the subscribers page as a newsletter that they can subscribe to. Also, when you send a newsletter out from the "Create/Send" tab you will see these type of newsletters in a dropdown box to select from."
Anyway, the idea being to make this clear as to what it's used for for the first time user. By no means is my wording all that great but anything is better than nothing and all as it takes is adding a markup field to the form.
Add New List Form: Category Field:
What purpose does this have? Does this mean that when I newsletter is sent a node is created automatically for that newsletter and I can find it by searching for the tags put in here? Something else?
Add New List Form: Send Rate Field:
Does this do anything or is it just a reminder of what we intend to do?
Add New List Form: Custom Send Rate Field:
I don't get this. What does "Once ____ nodes ....." The reason I don't get this is from what I can see of your module you don't use nodes. You create your own templates from which newsletters are sent. Now, even if you did create nodes, wouldn't there be one node per newsletter so why would you have a setting of "something nodes". A would appreciate some understanding here.
When I look around enough I'll figure out the answer (I knew it before as I did set it up and have it all working) to the above but this is my first impression looking through the tabs and of course that's what everyone is going to do first up.
Subscribers: Obvious and clear
For me, by the time I got to this tab it was making sense but it probably should have some markup explaining that the templates here under "Mail Templates" will show up on a dropdown box under "Create/Send" just for the sake of completeness.
Settings: Obvious and clear to me