S&T,
thank you for your kind words.
(I don't know about chairmanship and guidance, I only try to figure out facts, and enjoy much of the very contentful discussion in this thread. We also found it useful to provide a concise summation of the known (and some speculated) facts and causal relationships in this accident with the help of a WB-Graph.)
So I wonder if it might still be fair to say that any hesitation in braking was a natural reaction to the knowledge couplet of a reported slippery runway and any 'feeling' after touchdown that indeed it was so.
I think the most important fact why we can dispel this theory, is that the pilots selected autobrake MED, which would have started applying brake pressure two seconds after being triggered.
If they had envisaged careful or delayed braking to avoid hydroplaning and/or its consequences (brake asymmetry comes to mind), they would have opted for manual braking from the start.
Bernd