On a more philosophical note; Put yourself in the shoes of
first(). It's a method, doing an important job in the Craft eco-system. It prides itself on returning the most important and relevant data in an efficient and unencumbered way. Serving up entry after entry, asset after asset, 24 hours a day, all week, all year. Never complaining, never getting any praise.
And you want to treat it like a simple property? As a dumb, brainless reference to some data that some other method created? How do you think that makes
first() feel? How would you feel if someone treated you as property?
I know you're a good person with a big heart, Mats. I'm sure you will do the right thing and treat
first() with the respect it deserves, even though it means that you'll have to write a few more characters a day.