As far as I know, OS X can not "tile" in the way that Windows can. It could be for several different reasons. I can only think of a couple like maybe they thought it wasn't used enough to implement it. I've used Windows since 3.1 and I can count on one hand how many times I used the tile feature. Of course when I did need it, it was nice to have, but I don't really miss it either. The other reason I can think of is that they found that people only used tile to find a browser window fast without having to flip through all the windows and to find it visually. But that is what expose is for.
As far as the appearance of the GUI, it's not very customizable right out of the box. There are programs written to change the things you are talking about (I think). I'm not big on doing that kind of thing so I don't have any programs or links. I'm guessing Apple doesn't like giving people choices because they like their stuff to look good. I've seen people change colors, fonts and font sizes in windows that looked like a nightmare. You could argue that if they like it, who cares, but Apple has an image to protect in some ways. I'm an architecture student, and if I designed a building to look a certain way, I would be horrified to see someone deface something I took a lot of time in making look good. To me it feels the same way with apple. They make it difficult to change how things look for a reason.
If you need to change those things because they are hard to see, the only thing I can think of is the zoom/contrast features in the Universal Access section of System Preferences.