Well, I don't have a strong opinion on them myself, but I can offer you some reassurance: this is Linux. There's always at least a few programmers grumpy enough in response to any kind of change that they'll do something about it and provide some option to use the old thing. I'm sure the tango icons will have their own legacy icon theme soon enough, if not already.
There are dozens of icon themes available. They should already mostly work because, according to the post, XFCE has moved to the standardized icon naming.
