You are not alone.

Every 8.75 diff I've ever owned roared at highway speed. Probably pinion bearing, I just live with it because I drive them so little, but hate it just as much as you do.

I've been waiting for someone to upload a Youtube video of how to do a full re-build of the 8.75 so I can know how to do one, but still no one has done it.

The 9.25's in the Rams are only a bit better but, same thing: pinion bearing replacement is required reading for a Dodge Owner.

The Dana that was in my diesels I didn't own long enough to comment, but I sure don't hear the 2500/3500 Owners complaining about them, so you might be on the right track with going the Dana route.