Lets start off with the name PHOTO-shop, the PIXEL-BASE program. Unless you are editing photos or using a lot of textures, I see no use of photoshop to a graphic designer. To this day I still receive photoshop files of full website designs. Now before I get flamed too much, I know that they share very similar capabilities. But so does a car and a bike. They both take you to a desired location, but you rather not use a bike if you're traveling for miles. This is the same frustration I share with photoshop users. Let's remind ourselves that illustrator is a VECTOR-BASE drawing program that allows you to manipulate shapes with their anchor points. Meaning you can snap, bend, add, curve, or scale every point of a graphic without compromising the quality. You can re-use parts of the same element more efficiently, you can scale things 10x faster than what you could do in photoshop. Illustrator has so many advantages and if you're a new designer and you haven't made the switch you should do it now!
1) There's two steps separating you from the align tool in photoshop and in illustrator there's none. If you don't currently use the align tool then I suggest you start familiarizing yourself with it now. It's a tool I use every day.
3) Resizing in photoshop is bad. We all know business cards, T-shirts, web advertisements android, or iphone all have different graphical size requirements. Let's stop pixel stretching today. We can do it!
These are just a few out of many.