This is one of those inexplicably annoying features of Apple products. I love them and give them money, but find it utterly stupid. However, I'm sure you'll shortly be barraged for questioning it, so I apologize in advance.
Same here. I don't always do the upgrade all and only want to upgrade a few important ones (low bandwidth) and hate tapping one, then pressing home then tapping app store and starting all over. Why do I care to see it install, I will go run the app when it is done.
Another issues (that was finally fixed) that has annoyed me from day one and Apple did not stick to their own ui guidance was the app store scrolling between pages. You had to click the little arrows in the corners to change pages and I was always finding myself trying to scroll left or right. But they did finally fix it years later.