"the root isn't ""wet"", it is most peculiarly ""wāt"".
The long o is not ""the lengthened o-grade of the short e in the ablaut system your author didn't like very well"". The long o is the Germanic reflex of pre-Germanic long a. ""Wōdinaz"" is proto-Germanic, not pre-Germanic. The pre-Germanic is ""Wātinos"". The difference between the two also drives home the point of making a distinction between pre-Germanic and proto-Germanic. As for the barred d for the proto-Germanic /d/ phoneme, that's just one possible convention for writing proto-Germanic. Take it up with our Proto-Germanic article, we should aim for some consistency across articles. 
As for a source, I agree that Pokorny is just useful for an overview of non-Germanic cognates, not for an in-depth discussion of Germanic etymology. For that, we have the perfectly academic, recent and insightful article by Rübekeil, which has been referenced in plain views since about 2006.  (𒁳) 

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