I think most things have been addressed already by Keith or others, but:
1. Sorry to hear that the new interface isn't universally loved, but what is? We like it, a lot of people like it, and it's here to stay.
2. The lack of colors on the intel summary icons is a temporary thing, an artifact of the porting. Same with things like the missing health percentages on the selected ships box. Please don't generalize minor nits like this into a distaste for the interface as a whole.
3. The "medieval" font is actually the... font from the AI War logo.
Always has been.
4. Almost definitely no smaller fonts coming. You can use a larger or smaller fullscreen resolution to make the fonts and everything else larger or smaller. Bigger fonts aren't going to give anyone eyestrain, that doesn't even make any sense, but the fonts are the size they are because of people complaining of eyestrain in the SlimDX side. Making these variable-sized would be a pretty gargantuan nightmare for us at the moment, and the handy-dandy screen resolution lets you accomplish much the same thing.
5. Regarding pretty much everything else, in terms of ships and everything else that you'd be looking at, it's either the same size as before, or larger. And in general the contrast is higher now, except in a few, temporary, niche cases that were cited in #2 above. I don't see how there could possibly be more eyestrain here than there was in the older versions, in other words, unless people are now playing at a higher resolution than before or something.
6. The graphs are also something that only went away temporarily. We could only do so much in time for the 4.0 release, and if we went chasing every last feature from the SlimDX side we wouldn't have finished in time to stay in business past this month. It's all stuff that was fairly peripheral in the first place, though certainly I really liked the graphs, too. And that stuff will make a comeback in the coming months, assuming we're in a financial situation where we're able to do that.
7. Putting the rounded buttons behind things such as on the galaxy map text is for contrast. Those don't add to the size of the text on the galaxy map much at all, just 2px horizontally and vertically. And they let us render the text without having to have the text borders, which is a MASSIVE reduction in cpu load, as well as solving the old complaints of "fuzzy" fonts from some folks in SlimDX, as well as simply looking cleaner.