I was planning to write up a giant wall of text about my thoughts on the icons today, but it looks like eRe4s3r already beat me to it and basically said most of what I wanted to. I did intend to put some examples of other games that have dealt with icons that came to mind earlier this week, so that'll go below with a bit of added rambling.
Assuming icons are a given, Blue's more recent, minimalist icons are definitely on the right track for a game of AI War's scale. I think it'll have to be accepted that you can't manage to have individual icons for every single ship type in the game that are meaningful without introducing some combination of a) a significant frustration factor for new players and b) sensory overload for everybody else. Making the distinction between what information
needs to be communicated in an icon on the map itself and what can be relegated to an informational pop-up or other GUI element is critical.
I still consider Supreme Commander: Forged Alliance to be the benchmark for meaningful iconography in the face of huge numbers of units. While this doesn't translate 1:1 to a game like AI War, there are still lessons that can be applied.
For each non-experimental unit, there is a small
icon situated above it. The shape of the outline, the insignias contained within the outlines, the level of the unit indicated by the small vertical bars underneath each icon, as well as the health and (where applicable) energy bars tell me the general disposition of my force at a glance. The icons do not communicate minor stat differences between the various tier 2 assault tanks or tier 1 assault bots, as that information is relegated to tooltips, but an experienced eye can tell in about 2-3 seconds that this army is geared almost entirely toward a land battle (with tanks, bots and artillery) and has virtually no anti-air cover.
The game also does not specify these same icons for the huge experimental units, because each of those is sufficiently powerful and visually large and unique that an icon would be effectively meaningless. They instead get health/energy bars as applicable (in this case, just health as none of these units have shields).
A key difference here, though, is that while both games are played on 2D planes, AI War allows for and encourages more camera rotation in a full three dimensions, both because it's in space (who doesn't want to rotate a camera in space) and because ships like the Ark have a vertically-oriented design that is inherently less appealing from a top-down perspective. Furthermore, the current AI War icons hover a significant distance above the units they represent, rather than being overlaid directly on top of them like in SupCom, which leaves open the issue of icon overlap yet again. Shrinking the icons down and/or implementing a spacing requirement on ships (so 30 squadrons don't stack on top of one another) would potentially help, though the spacing requirement would probably introduce gameplay changes that aren't wanted and isn't really a serious suggestion.
Another game I have a ready screenshot example of is Wargame Red Dragon, which has significant numbers of units in close proximity to one another with large icons displayed over the top of each unit.
The
options menu allows for significant customization of these icons. The setup I was using at the time shows the NATO icon for the unit (indicating if it is infantry, anti-air, artillery, etc), the number of units in the group (always 1-4), the name of the unit, a binocular icon if needed to indicate if the unit has any recon optics, a number in parentheses indicating how many soldiers are in the group, a vertical column with a yellow bar showing the unit's supply capacity if it has any, and then optional flashing icons on the right to indicate if the unit is low on fuel or ammunition.
As you can see, while the icons are individually very informative, things get nigh-unreadable just above the center of the image. Even I can only make out a fraction of what's actually there with 200 hours of time in-game. Even though the game allows you to merge icons (condensing that indecipherable mess into a single horizontal line of NATO icons), you lose
all of the other information, leaving you uncertain of whether your cluster of six separate tanks is entirely out of ammunition, or your blob of infantry is composed of a stack of single troops instead of squads of 10. Similar issues could arise in AI War now that, for example, fighter squadrons exist, especially if discrete fighter survival (i.e. 2/10 vs 7/10) is a meaningful gameplay element in its final form.
And on the subject of sidebars, they could be awesome, especially if it were coupled with some kind of vastly simplified icon system (if only to have a basic symbol/highlight to tell the player that there are ships there). That sounds to be more like a Sins of a Solar Empire GUI style (which was just posted about as I was uploading the images for my own rambling wall of text), which even comes with small overlays for fighter squadrons rather than icons floating above them when zoomed out. Both the base Sins game and the recent Star Wars Supremacy mod have some UI examples I'll leave below to cap this off. There are all kinds of ideas already out there, and maybe there is something to be gained from borrowing a few of these where appropriate rather than trying to completely reinvent the wheel. Just some food for thought.