I made my second attempt tonight at playing this game. This thread seems like a good place to put my comments instead of creating a new.
First good impression: It works perfectly in WINE in Linux! Great! Of course native Linux (and MacOS etc) support would have been better, and hardly difficult to do, but being able to play at all without rebooting to Windows is wonderful. I think the scale of the game is perfect (more/smaller units would have been too much work to keep track of on a computer screen), and I have looked forward to playing this a long time. I own three boardgames covering the same situation (strategic WW1 in Europe) and a forth that was recently released and should arrive here any day, but I have always wanted a computer game as well (to play against the AI only... human opponents are a lot more fun to play over a real gameboard IMHO). I am very happy that this game was published, and I didn't hesitate to buy it the same day I finally noticed it had been released (a month late... but anyway).
But then... The UI... I thought it was the fact that I played in a Windows Emulator that caused many of the problems. But after installing and playing in Windows XP I realised that it was just as bad there. Both my games ended before turn two, as I just couldn't stand fighting the UI, and I have played wargames on the computer for 20+ years so I should be able to cope with almost anything (or so I thought).
First warning was when starting the game I have to click the arrow to go on to setup. Why? It is nice that in 1.1 I at least get a popup first telling me what to do, but why not put me in setup mode directly? If I want to see the map without units there is a button to do so. This isn't a killer really, but it got me worried about the UI quality of the game.
It is not easy to guess which buttons are nation-specific and which applies to all my nations. It seems as if the diplomatic screen is common to Germany/A-H when playing CP, but it appears with the buttons that show up only when a nation is selected.
Limited, if any, keyboard support. I hate to have to bring up the context menu to order units around. Perhaps there are undocumented keyboard shortcuts? Perhaps they can be added in 1.2? It would make the game many times more playable if I could hit M for move or B for barrage etc (no F-keys though please... single letters are very nice and easy to remember). Same for bringing up the different dialogs (and again, no F-keys please).
There is very little feedback about what is going on. It would be nice if the selected unit were highlighted.
It would be nice if when I select an artillery unit I would somehow see what hex it has been ordered to barrage (if any). etc
There is no good and consistent way of getting out of dialogs. When I press the production button I can get back to the game by hitting ESC. If I press the refit button and then press ESC I get a question if I want to quit the game. It would be nice if ESC (or backspace or the right mouse button or ...) could always and consistently be used to do "back"/"cancel" and some other key for "OK". I don't want to chase a small OK/Cancel button with the mouse pointer.

A consistent way of deselecting things would also be nice (sometimes right-click seems to work, sometimes left-clicking outside of selectable hexes).
And while at the subject of the dialogs: most of them are not very easy to use and give very little feedback. Sometimes I click a button and it seems like nothing happend, and I do not know if it did or not. And important things such as the cost of upgrades can only be seen in the manual (or the faq).
The diplomatic screen shows only countries that are neutral. Shouldn't there be any way of getting a report on which countries are currently with me or against me in the war?
And since I can not interact with the game board while in a dialog, why not let the dialog cover the entire screen instead? That way perhaps they could have enough room for all the needed details?
When setting up pre-game there is firstly the problem of no visual indication of which unit is selected. Then there is no way (I have found) to easily pick units within stacks. I can right-click to "shuffle" (more like "cycle through" it seems), but then when I left-click I get the same topmost unit anyway (not the unit shown after the shuffle). To move units around I end up doing a game of Towers of Hanoi to get the units I want where I want them. (The small positive effect of this is that it gives the game a nice boardgame-like feeling.

).
The warnings when going from the activation phase without having allocated all air support or activated all HQs could provide more information, or be removed. I still haven't quite figured out how air support works, other than that I sometimes can click an enemy stack and select air recognozation. And why is there a warning when I have not activated all HQs? Perhaps it should be more important to warn me when I have not set all artillery units to barrage, or moved all activated units, after the orders phase? Perhaps it would be better to just have a generic "are you sure" when the player wants to end a phase?
The whole naval aspect of the game is just confusing. Nowhere in the ui or in the manual are there enough information to tell me anything about what is a reasonable strategy to use for my ships. The ui does not give me much feedback on what is going on. I do see some counterstacks at sea that seem to indicate which units are located there, but there seem to be no way to issue orders to them there or even inspect their current status/missions. The naval dialog isn't very useful either. I think removing this part of the game would be an improvement (perhaps make it optional in the future?) and let us concentrate on ground forces. Or make the ships appear as tokens on the board the same way ground units do to make the UI more consistent perhaps?
I have tried to figure out how terrain works. It seems cavalry can never enter non-open hexes. I have not been able to find any movement advantages of cavalry that I see mentioned in the forum, as I only seem to be able to move units one hex per turn regardless of type (and I haven't been able to strat move at all, but perhaps the CP do not get any rail points until later in the game?). It would be nice to have a table of the terrain effects, like is common in boardgames. I know I can see terrain effects after a battle, but that is of little help when planning, and it still does not tell me the effects of terrain plus river crossing (or terrain plus town) when both may apply as far as I can tell. (What effect does rivers have, btw?)
It is not easy to tell if there is some kind of "ZOC" in the game. Will hexes adjacent to my units be difficult for the enemy to move through or trace supply through? It would be good to have an idea of the rules on how supply can be traced and not.
I still wonder what the big grey area in the lower left of the board is used for. Perhaps it will become obvious later in the game?
I will give GoA another chance after next patch (and each following patch), but in its current state it just is not playable. Sorry if I sound too negative.

I hope to return here with many positive comments after the next (or some later next) patch.

I'm sure there is a nice game somewhere hidden below the UI. It seems promising after reading the comments from those that have managed to play it.