I think at least another difference is that in WW point 5 actually breaches the extension of the 1-3 line.. whereas in wedge it doesn't. Apart from that wedge as a pattern doesn't have a pattern target.
But in general my feeling about the entire focus on volume is that markets have changed a lot from earlier and keep on constantly changing. My personal feeling is that volume as an confirmation indicator no longer provides meaningful or valuable input. I see it specially in international mkts, be it equities, fx or commodities.. most often volume is erratic and doesn't prove to be a meaningful indicator. Most ppl trading US equities complain the rise in S&P is with very little or low volumes and thus the rally doesn't have legs or is weak and doesn't have strength. But that has mostly proved to be false over the last 3 yrs.
Also, in our markets now there are lots of ways to take positions - cash equities, futures, options - buying & selling both. Plus futures provide leverage also. So many things. Thus what volume does one actually look to take a cue from? Cash/Futures? or both together? And how do you derive information from volumes in index options, as a lot of trading now happens there? Volume there could mean anything depending whether one is buying or selling and calls or puts.