I am not a huge fan of the current look of the main menu. I think the title should definitely be separate from the "background" (the moving ship). No harm having it on the ship as well, but right now the title screen lacks the title. The button layout works, I prefer vertical menus but it really doesn't matter too much so long as they are well ordered and don't interfere with the background. I think expanding menus would be good if there are too many buttons though - multiple rows of buttons would be too much.
As far as the Endless series, I have heard a lot of people recommending their UI over the years. I haven't spent a lot of time with their games other than Dungeon of the Endless. What are some of the particular things they did with their UI that you think would be useful in AI War 2?
I get what ilitarist is saying about them ignoring their mistakes: I was playing Endless Space 2 the other day and was frustrated in managing the different species and setting my planet-tier bonuses. These options are in a menu screen that can only be accessed by going to an entirely different menu screen. (I think the species management is accessed by going to the political screen and then clicking on the population survey, as an example.) Ironically, both of these management systems involve using your luxury resources stockpiles... the same stockpiles ilitarist was mentioning were a pain to manage in Endless Legend.
I'm not the one you asked but I can tell you what I think is good about EL/ES UI: presentation through fonts and layout. It looks like an Apple customer site or something. You can probably see that even when it's inconvinient in ES2 you still got nice font and spacing.
This is a bit off-topic, but I'd like to intrude in the discussion about what is so good about the UI from the Endless games. It is not a single big thing, but a lot of details that add up better than most 4X games. First, of course, the games are gorgeous in general and the UI just plain looks good. This makes a lot of difference.
A big part is that it is generally very easy to navigate (with exceptions). You click on stuff and it just takes you to the appropriate screen - click a hero to manage him, click on a tech to go to the tech screen, a quest location to go there in the map, a unit to go to unit designer, etc. Right click closes any screen, no need to click on a close button. Menus and lists are often collapsable to save space or see a bigger list or whatever. Just mouseover anything and it will generally show you what you need to know in a nicely formated tooltip - no need for a dedicated screen or an in-game encyclopedia or an online wiki. (But when the tooltip does not tell you enough, you are generally screwed - making it somewhat hard to teach the more convoluted mechanics). You can also interact with stuff from various places - you can assign a hero to a city from the hero screen, the city screen, the system/city list. This list is also awesome - most 4X games have one, where it lists the yelds of each colony and what it is producing and etc. But in the Endless games, you can switch the production from here, assign heroes, change population from one planet to the other, or click on a system to just go there and see more details.
It also conveys information in a very visual way. It uses plenty of symbols, color-codes everything, uses boxes and cards to format "tooltips" when you mouseover, have visual effects for most things happening, etc.
It has all the quality of life features most recent games have: neat alerts every turn in the side of the screen, zoom out abstracts the maps, good sound effects, diplomacy shows you what the opposing AI will accept, etc.
I never before heard someone say the UI was inconvenient, quite the opposite - with Endless Space 2, people said it was super convenient but hard to learn. I myself often find it hard to go back to other 4X games after playing Endless Legend for example, it is just annoying. It has some glaring fails: systems like stockpiles or minor factions are hard to figure out, some screens are bad (like quests in Endless Legend or politics in Endless Space 2)... but people still like it much better than Civilization 6 or Galactic Civilizations 3 or even Stellaris - and in 4X, the bar is quite low (Distant Worlds, Aurora 4X, Master of Orion 2). AI War Classic is generally on the bad side but has some cool features.
Now, as far as how this is all applicable to AI War 2, I'd say it isn't easy to just translate as the games are very different. Maybe try to use somewhat similar layouts for tooltips and other stuff? The main menu isn't a particularly strong point in the Endless games.
