Part of what is needed to deal with the wonder spamming runaways, judging by my current game, is more aggression. Austria wouldn't be a runaway with 19 wonders if her 2 warmongering authority neighbors had done the authority thing and attacked her effectively in the early game. Only lately (at around turn 280) are The Iroquois and Denmark trying to push her, and I rather imagine they'd have been more successful if they'd never let her get the huge tech and social policy lead she had when I first met her to begin with.
Of course if the AI acted that way I'd have never found out about this, because authority Rome and Persia were my neighbors and they'd have obliterated me long before caravels. But details. Point is that so long as they are not completely isolated, wonder runaways could be regulated with some good old fashioned war. And this would if anything make the game harder for players, too.
I do think there's some merit to the point that the AI getting payed for building a wonder, which is already a very rewarding thing to do, may be too much in the way of payments.
EDIT: On the matter of the AI it is also worth pointing the positives. In another of the games a I played with this patch I suffered a pretty well timed attack by Songhai. He must have declared the second he had his UU ready to produce because it was actually mostly chariots and a spearman at first, but then his cavalry landed behind my city, which was not only surprising but meant that he was actually using the amphibious promotion from his UA.