The W8 is noteworthy because like Ferrari and F1 8-cylinder engines, it uses a 180-degree (a.k.a. flat-) crankshaft, with offset crankpins for an even firing order. This would give a very distinctive exhaust note. Second-order horizontal shake is dealt with using balance shafts.
I'm really sorry about the death of the W8, to be quite honest. I guess only an engine geek like me can fully appreciate it in spite (or because) of its elegant complexity... However, with already a comparatively very compact conventional V8 as used in the Audis, there was no justification to keep the W8 in the program. Several years ago, I predicted -- and still believe -- that VAG will come out with a flat-crank V8 for top Audis and maybe even some Porsches. It might come in the form of a smaller displacement than the current 4.2 litres (3.6 would make sense) and be forced-aspirated. It would seem to be a logical replacement for the 5.2 V10 used in the RS6 and V8s to be used in the Porsche Panamera.