Personally, I think Firaxis has gotten carried away with pulling the teeth from UU's. The Prat's are about the only one left that is anywhere close to being what I want in a UU.
Basically, a UU should be designed so that if I'm next to a civ, when three things should be true...
1) The AI WILL build the UU in larger numbers than if it were a 'normal' unit.
2) The AI WILL almost always go to war to take advantage of the UU.
3) If I'm the one who it goes to war with, I need to do something significantly different to respond to the UU compared to if it were a normal unit.
Firaxis seems to be making #3 always 'false'.
I want those 3 to be true because it will generate more interesting differences from game to game based on whom you're next. Without those 3 being true, from a military perspective, the UU your neighbor has is pretty much irrelevant.
Let me give you an example of what I DON'T want it to be.
I start next to the Egyptians. I know that they may be building War Chariots. Do I build lots more Spearmen than I would against a civ with regular Chariots? No. If I can't build Spearmen, do I radically alter my research path to generate an unusual defense against them? No, my own Chariots can do a reasonable job of counter attack, and the Archers in the cities can put up better than a 1:1 defense.
So basically, the Egyptian UU isn't powerful enough to make me play the game any differently than if the Egyptians had no UU whatsoever.
Now here's an example of a UU that IS properly setup. The Roman's Prat's.
If I start next to the Romans, and find that the first 2 of the 3 things on my list were true, than the Prat is powerful enough to cause me to alter my play. I WILL build significantly more Axemen than I would if it were just normal Swordsman next door. If I can't build Axemen, I'll do something really radical elsewhere. Perhaps I'll trade my only Horse and only Wheat (or whatever) resource to a civ in exchange for Copper so that I CAN build my Prat defense. Or perhaps I'll adjust my research path to get Fuedalism much earlier than I normally would, and run Vassalage more than normal to build Shock promoted Longbowmen as my Prat defense. Or perhaps I'll do some diplomatic trick that handicaps me (like adopting the Roman State Religion even though I only have one city with it in my civ and all of my cities have the religion I founded), but helps insure that I'm not the target of the Prats.
In any case, the point is that if I think I'll have to fight Prat's, I WILL do things differently than if I were fighting other civs.
All UU's should be that way.
And to tie this back to the current thread...
Redcoats in Vanilla Civ were about right -- i.e. you needed to do things differently if Redcoats were next door compared to regular Riflemen. But they've been de-fanged to the point were you don't have to do anything special. Maybe build one or two more Grenadiers, but that's about it.