First of all I want to say that I'm a proud user of "themaPoster"!
I used Multi Poster (4 & 5) and it's a lot slower and not multi taskimg (when you publish a post you can't edit another posts).
A few things that I think are better (more friendly user):
1. The forums prefix - Instead of "multi" I like when on my posts the tag is "[FS/FSC]", and to change it I need to go trough all the forums and change it one by one - I suggest to make an option to change a single prefix to all forums.
2. The forums list - The are few folders like "My Forums", "Adult A-K" and so... so there is no place where I can see all the forums I set a user to them.
3. Sections - There are all the sections that automaticlly comes with "themaPoster" I'd like to have other sections but I want to delete the original sections and I can't.
4. Adding forums id - On MultiPoster there is like a table where on the lest column the section is displayed and on the right column you enter the forum id, instead of the dropbox who does the adding id numbers a lot more complicated (think about it
.
5. Saved posts templetes - I have a constant templete for TV Shows (for example), and instead of designing everything from the begining in every posts I saved a templete, but It's not comfortable to use the existing method from the menus above... there is also a problem that when you want to update a templete you need to save it as a new templete and to delete (manually) the old one, and the new one added at the bottom of the list.
Hope I helped