You say: "The hope is that this would encourage water to stick to the material and slide down it rather than bead up and drop off."
True enough, but it's still going to be very WET, and if you touch it, some of that additional water is going to douse you or your equipment.
Others were talking about the unwoven material used by Bibler, and earlier by Early Winters to line its GTX tents. The idea is to soak up the condensation, and hold it until it has time to evaporate. It also doesn't feel as wet when you graze against it, because the water has been absorbed and is not just sitting there on the surface.
With the microthin coating, there is nothing to aborb the water, so it will just sit there, or perhaps hang there would be more like it.
If Jack and some others are right about the condensation not forming so much on the PET, or Mylar surface in the first place, that sounds better. Even better if there is netting (that also keeps out bugs) on both sides of you and high enough at head and foot to protect you and the bag/quilt/hat from water contact. Or it could be sub one ounce fabric instead of netting if you like that better. TarpTent seems to like the netting on some of theirs, but no Cuben with them, of course.
In your later post, you shift from water dropping to "misting." This word gets thrown around so much, I'm not sure people know what meaning is intended. Some are talking about fine condensation that looks like somebody "misted" the tent wall with a sprayer. This can be common in a cold, heavy rain in a silnylon tent, even if no one is in it. Others are referring to very tiny water droplets penetrating through the tent wall and falling slowly, like a mist. The latter is addressed by a material with good water resistance. The former is inevitable in a single wall tent, the only thought being that if Jack, et al, are right, it will be less with a Mylar surfaced material.
So it sounds like you hope that the Hydrophilic coat will keep that lesser amount of condensation on Mylar from dripping. But it might also remove the tendency of the Mylar to reduce condensation. Please let us know how it all works out.
In the meantime, I suggest the best avenue is to find very light WPB coatings or treatments that water vapor will permeate through at lower humidity pressure, as you would have in a tent, as compared with a jacket during exertion. Some mentioned in Alan Dixon's article on this site are Event, Nexus Epic, Propore and maybe the updated verions of Entrant being used by Montbell. There are serious water resistance issues with Epic, the lighter Propore materials available are very fragile, the Montbell material is probably not quite breathable enough - so that leaves a very light version of Event. That's where I would suggest looking.