The aqua plugins are not bad... but nebula 4 would be even a lot of more interesting for plenty of people out there because there are plenty developers around nebula who would do plenty of libraries for lesser money than aquas...
It depends. Multi-frequency library, plus protection, plus mini shop VAT, plus skin. We don't know if library developers will able to hold the same prices for Nebula4.
and that together with nebula 4 would be awesome if latency and cpu is no matter in future
OSX and Windows are not realtime OSs, also your AD/DA has latency so you always have latency. There is already 72 core CPU so CPU matter is a budget matter, specially on lasted Nebula/Acqua engine with CORE6, SSE4, Vector compression, etc.