1. Holy Roman Emperor is probably tops for me, just because I don't want to conquer city states, nor feel like I'm not playing the civ to its strengths if I'm not doing so. Hard to turn your nose up at an extra policy slot, (even if extra Military slot is going to be the least valuable one, to me), and the rest of Germany's complete package is pretty solid, but man, I don't like that City State bit hanging out there. I hated it in Civ5 when Mongolia had it, and I don't like it any better now. Other warmonger abilities don't tend to jazz me, but at least I can envision how I'd play them if, like, I made a game with only the most punchable AI opponents, and turned off every win-con except for Domination. "Holy Roman Emperor" doesn't even give me that.
2. Swift Hawk just doesn't work well, and at best conjures up the idea of a slogging, dragging, never-ending war game ahead of you, like an Alexander game but not as successful.
3. Bannockburn is here for reasons stated above - it's too situational, hard to swing towards your advantage, and would make much much more sense being about wars of reconquest. I like the rest of Scotland's design, or I guess I should say that Scottish Enlightenment is the headliner there, the Golf Courses are nice-enough flavor and help assist the CUA, and the Highlander is, well, it's an easy 4 era score points and comes right around the time of corps so it's not too taxing to prepare for it and pop a couple scouts out, pair 'em up and upgrade them for a quick clean-up unit. But Bannockburn, like Radio Oranje, feels like an empty ability more than anything, but Radio Oranje at least gets you something, even if it's not particularly noteworthy.
And I'll defend Georgia's abilities as being fun and interesting when you're dedicated to playing their way. Especially with Dramatic Ages going. I mean, I always have Dramatic Ages on these days, but with Georgia it's basically a must.
All that said, I finished my first Vietnam game yesterday, having been put off for a while by seemingly (to me) lackluster bonuses that I couldn't make heads or tails of how to best take advantage of. I finally decided to just roll up a hot, wet continents map and go in without a plan, and I ended up having maybe the most fun I've ever had with this game. Hard to tell how much of an effect Nine Dragon River Delta had, especially as the game doesn't make it easy to see those yields, but I was flying the whole game, and Drive Out Aggressors made easy work of Genghis' attempts to conquer me (though the Voi Chién wasn't a ton of help there, since it was, you know, Mongolia. Still a strong and versatile unit.) Anyway, point being that even abilities that seem unexciting on paper can lead to cool and different game experiences.