I'm using version 2.9.2 of the plugin on version 3.4.2 of WordPress. To make things clear: the UI's fine as it is - the problem is that there are very many options, many of which inexperienced users (like me) won't grasp right away. I just went through the options again and modified a few of them because after using the plugin for some time, I get a feeling for what the options do and what I really need.
Like with all powerful tools it probably provides far more options than your average Joe User will ever need. Take Microsoft Office for example: the majority of the users will use only a fraction of the possibilities that the tool offers.
A possible solution might be to distinguish between "basic" and "advanced" features. With ease of use in mind I'd think that most of the users of the plugin will want to create a map, put a handful of markers on them and pretty much don't care about the rest. So maybe it would be a good idea to offer a "basic" or "reduced" UI with only the most important controls and an"advanced" or "expert" mode with all the controls visible - it'd be perfect if you could toggle this with a click on a button and set your preference in the settings.
My favourite solution would be that could could toggle each field seperately in the settings for "user defined UI" and on the layer- and marker-editor have an option to toggle between "user defined" and "display all controls" - a third (non-customizable) basic view might also be an option.
The basic view for a layer could - for my taste - use only the fields "name", "layer center", and the preview image. All other options could be hidden behinde a "expand to see more options" link. For a marker editor, I'd chuck everything behind the "more options" link except "marker name", "add to layer" (quick side-question: can a marker be added to more than one layer? Might be useful...?), "coordinates", preview image and "popup-text".
There are several strategies to achieve that, you could, for example, display the current setting (in many cases the default value) as a static text and display a "change" button or link. This has the advantage that you visibly reduce the number of controls by a great deal while still providing access to everything. A perfect application for this approach would be the Icons list: it totally overwhelms me each time I edit a marker - and I end up using the default pin all the time. So show the default marker (let the user change it if he fancies that) and add a "more pins..." link and pop up the whole list only on clicking that link - that'd be 177 radiobuttons less on the main page.
Another approach could be that you hide the "advanced" options altogether behind a "show more..." link. Pro: maybe easier to implement: con: you can only choose between all or nothing. The most user friendly way would be to allow the user to choose exactly which fields he wants to see in his editors. UI design is somewhere halfway between science and art. There are basic guidelines which have proven useful (like the "ease of use" paradigm), but it also has much to do with personal taste and preference. It's no easy task and I don't envy you doing it, however I *very* much appreciate your work.
As for the bulk import: I'm glad to hear it's in the queue because I think that might be a feature useful to some people. As far as the geotag data from images is concerned: I think I read somewhere, that some wordpress upload methods might strip EXIF data from uploaded pictures - don't know if that's really true but might be something to check early. Otherwise I think the idea of using galleries is probably the best one: let the user put all images he wants to put on a map in one gallery, then simply check all of the images for geotag (and maybe time (for KML animation)) information. If more images are added to the gallery later, you can always re-check. You could even go as far as determining the map's initial dimensions from the imported data - if the user wants to change it later he can always do that. But that's only my wish list - let me repeat from the beginning: I'm very happy with the plugin as it is right now. Thank you very much for the good work!