#1 rarely happens frankly and #2 shouldn't happen if you are good at monitoring your diplo situation
YOU should be the one on the offense
I wish people would quit judging by their own experiences and assuming that everyone has the same thing happen. I generally play with 2x the number of "default" AIs (in fact, I changed the default to that amount), which makes for a more crowded game. A more crowded game makes for more wars, and I
am going to get declared on at some point. This frequently happens in the early/mid medieval times. And when there are 6+ Civs in your immediate vicinity, I can't be "on the offensive" against all of them simultaneously. Nor can you manage to appease that many Civs diplomatically.
So in a situation where you are going to be forced to be on the defensive, the Khmer Elephant is a good defensive choice. Again, maybe you don't have many Horse Archer/Knights in your AI stacks, but I frequently do. The ability to specifically target them is off significant tactical advantage.
and whoever said the jaguar isn't that good hasn't used them effectively. in fact they can be quite good when used properly and especially when you are lacking copper and/or iron. the fact that they can be built immediately in all cities once you have IW means a pretty darned quick rush. and that's all you need really to get going early and start developing a larger empire (= key to winning imo)
If you've had time to research IW, then it's not a "quick rush". But yes, if you happen to find yourself without copper or iron, then having a resourceless unit is good. On the other hand, I can count on my hand the number of times I've been without both copper and iron. Of course, I'll be the first to point out that your experiences might be different. But the reality is, despite their resourceless nature, and their free Woodsman I, they are a decidely sub-par variant of the normal Swordsman. If I have a choice between building a Swordsman or building a Jaguar, there is no situation where I'd choose the Jaguar. That certainly doesn't qualify them as a good UU in my books.
Bh