Like on Rhodiums page there is a similar procedure where DMF is used, and the reation was done this way (but it was not explained in that case why), you'll see you can adjust the ratio of Pd downward. I mentioned in the serious chem forum that the ratios seemed excessive but I think this can be amended by adjusting the addition rate of H20 to coincincide with the reoxidation rate of the lesser amount of Palladium used.
And gabd I think you are right in regards to "i guess if we played with the reaction times"
I think it's just a matter of adjusting addition rates, maybe applying a little heat, and extending reaction times, but it's a very viable modification indeed, and it really makes sense when you think that water does slow the rate of catalyst coordination to alkene, after all DMSO is not hard to find.
