I think Austria is the most colorful faction in the game.
France right behind it. And due to this France is my favorite faction. Austria is too colorful for me, the weird orange on the grenzers and blue pants don't necessarily tickle my fancy. France has just the right amount of glamour in my opinion.
United Kingdom is one of the more frequently played factions, my guess due to the easier ranking system and easy regiment creation. Just take a number and create a name or look one up. I wouldn't go as far as saying it is bland, though.
Russia is cool, I love the grenadier unit. I've wished for a long time that the Russian Militia would get a bayonet so it could be a playable class in linebattles. I mean think about it; a regular line infantry regiment only has two logical options concerning what unit they play, simbirskiy or grenadiers. They don't want to select the Leib-Gvardii because of its shooting (due to it being guard class). Or even remove militia as a whole and scrap it into a new infantry unit. Just my thoughts though.
Prussia is another easy one to play (kind of like UK). The ranks are easy to understand and develop, yet when it comes to history people have issues again. As for that, just check the resources on the Regiment List thread. They have regiment name sources for every faction in the game along with factions that aren't even in the game. That is a good place to start.
I agree with you in part about what you said about the Austrian Grenzers. They look really horrible, but they're only one of the units in the Austrian faction and I think the line infantry, footguards, riflemen, cavalry, and everything else looks pretty snazzy (In fact I think Austrian cav is the best looking in the game). The main reason people don't want to make Austrian regiments is probably because of how their uniforms were modeled into the game. I've said this many times, but I think Austria would be more popular as a faction if a little more effort had been put into making their uniforms look better in game.
France is nice but they're kind of generic as well. For some reason their uniforms seem like something a child would design, and even more so than Austria, where they just look classy. The french just don't look like real soldiers to me, even though many people would say that applied to the Austrians more than the French. The main reason French regiments are so popular is because they are some of the best documented in the napoleonic wars, Napoleon and revolutionary france is glorified, and they won the most victories in the NW so people are drawn in.
Russia is one of my favorite factions, if not my absolute favorite. Their grenadiers with those sexy hats, line militia, and partizani really make things interesting. They also have good cav. I don't know why people think Russia is boring and then praise UK when they're pretty much the same deal just with green uniforms instead of red. Obviously there are not many documented sources detailing Russian regiments, as stated earlier, but it could also be because Russia and the Russian language seems so foreign to people who live in western europe and the US, so it's much harder to relate to.
The UK has neat, orderly looking uniforms, but they are all the same and their lack of good cav and their overuse and the fact that I see that kind of thing every day makes them seem too bland and generic. I like them I guess, but not as much as some of the other factions.
Prussia is cool, and they have a lot of prestige surrounding their names even though they didn't perform so well during the napoleonic wars. I think I've been seeing a lot of new Prussian regiments sprouting up lately, especially as people leave the bigger Prussian regiments like the FKI, EPI, and EPG, and since they're used to Prussian rank structure and names, they stick with what they know.
Overall I think we could use some more Austrian and Russian regiments, but in the end it doesn't really make a difference considering that during LBs regiments rarely get to play as the specific faction or even regiment that their clan represents, so they just end up being another name on the scoreboard.
