Is the road buzz just getting to be too much on your hands? If so I'd just recommend some better gloves and/or to change the grips like roadtrip mentioned.

Since you're already running 32's I would keep it at that (going down to 28's will not help but rather make the road buzz greater). You can play with the PSI to see what works best for you; try doing 5 or so PSI less in front and see if you can see any difference.

It does sound like you'll end up on a road bike at some point but I too, would get some more miles on your current bike. I actually got a hybrid first when I first got into riding and then very shortly after I was stuck on wanting a road bike(!) although I had a bit more miles on my hybrid before I got my road bike.

You actually don't need much clearance over the top tube with road bikes but I do know some people that just prefer to have a little more clearance - it's all about what you're comfortable with. Remember that if you get into clipless pedals, you'll end up having a little bit more clearance anyways.

Also, as for road bikes always being agressive when compared to hybrids, that's not always true. Some road bikes are built with a more race inspired geometry while others are built more for endurance. The geometry will help determine the level of saddle to bar drop but by changing/flipping the stem or adding spacers will also allow you to get a more relaxed position on a bike that's built more aggressively-- and you can make a more relaxed road bike more aggressive by the same idea (flipping or changing the stem, removing spacers).