Obama has been in a few skits over his 8+ years in the public eye, sure, but very few of those skits are actually critical of something he's said or done. More often than not, they position him as the cool guy in some fashion.

Or their impression is so historically bad, as it was for years with Fred Armisen, that it's tough to gather if there is any point at all to what they're doing.

There have been a few, very limited exceptions. Compare the treatment any Republican in the public eye receives from them. Those are designed to make their target appear out of touch, foolish, weird, incompetent, etc. Even Fox's morning show has received more ridicule from SNL than Obama has. Why? People aren't having problems any more? The poor and middle class, to whom SNL attempts to be a populist voice, stopped struggling? The guy has no personality quirks or arrogance of his own that could be picked at?