Now, of course, no UU is truly crappy when compared to the base unit which it replaces. They are all improvements over the standard units.
In making the classifications, I have not attempted to list every characteristic, which would defeat the purpose of grouping similar UUs, but rather what I feel are the most salient features of each.
This is what I am talking about. Look at all the other groups Ive laid out, and then compare them to the last group.
When were Knights 12 str? are you talking about the UU Knight??? lol
The War Elefant in general is a strong unit. A UU based on a strong unit can't be sooooo crappy.
I played the Khmer and the Ballista Elephant once. I conquered 1 and a half civ with them, but mostly it was elefants against Axes, Catapults, Swords, longbows or Archers. So i must admit, the special effect came into play only 4 or 5 times. Not really decisive, but in theory it is a very strong special ability. As long as your enemy always brings horses to the battle you have guaranteed victories.
A small tip: You shoudn't choose Boreal or Ice Age maps with the Khmer, doesn't look good either.
The only problem I would have with them is that in about 75% of my games I will not have ivory. That would makes this unit non available 75% of the time (I don't have BtS so they might have changed that).
A small tip: You shouldn't play Boreal or Ice Age maps.
Ever.
Just out of curiosity: why? I mean I prefer fractal myself, it always gives a very unique landmass spread that actually looks like it could happen in nature, as opposed to the standard 2-3 ovals of continents, but I am curious why Boreal or Ice Age maps are bad.