After infamous price tag of Atmogen and Aphex Twin promoted Metasynth, there was Alchemy (my favorite). Now Izotope Iris and, on the similar technology, Izotope RX came. And I must accept that Iris made me very happy with how it made some beautiful sounds from some really horrible recorded samples of mine that luckily I never deleted. This tool encouraged me to use my recorder more. Iris is great for any Ambient lover. I was a little skeptical about visual synthesis after the prime days of Metasynth. But now I'm backing it once again. Reason is that it does not start to control your ears, which I realized, and as Spectral Layers by Divide Frames is awaited which looks far more promising than any of these tools could do till now.
I think soon spectral synthesis will have its own dedicated DAW. A workstation engine which is built in and around spectral synthesis engineering. At least I would love to see so. I started this post to know your opinion on this.