but my extra point is that even things that aren't supposed to emphasize caustics look more drab and flat without them
It's really sometimes just a few specs of light that make the big difference. If you don't look for it in a picture, you don't notice it but it makes the pic real. It can look plain wrong without it.
It would be nice to have some sim of it in falcon. On the feature list of the Cheetah-Website they are proudly mentioned without a remark like "Cheetah renderer only". I think, that would be necessary and fair to potential customers. But well, advertising ...
But my real gripe with falcon and glass is the black stuff which should not be there. I'm still not sure if it's reflection or refraction (or both; and you get it even with fully white background); in most other renderers it's refraction. But then you have some possibilities to get around it which plain don't work in Cheetah (like a bigger scale). With Cheetah you only have changing the form and the angle to get a good result (or putting on gold rims).
To tell the truth, rendering glass, especially drinking glasses, is a problem in any renderer out there I tested. Some are better, some worse, but in this case Cheetah is the worst (to be fair, in quiet a lot of other aspects it doesn't have to hide from the others). In other apps you can crank up some parameters and pay the price in rendering time, one has even built-in cheats for lower refraction bounces (changeable exit color and refraction blur). Even then lots of pictures with glasses show black rims.
And yes, with a real glass and a camera it's sometimes hell to get a good picture, too; dust, reflections and so on. You always end up with more or less heavy photoshopping. But black stuff in rims is in a photo always a reflection from the surroundings.
I still believe, cranking up the bounces would be the solution, together with fake caustics (and of course creating lights that reflect). But like I said, in other aspects it's a great software.