Every year brings a stream of beautiful new cameras and lenses. We all benefit from competition between the major camera manufactures, with improved quality and features. Though there are definite improvements, they tend to be incremental, not game changing. Some photographers get caught in the crossfire of this war between Nikon, Canon, Sony, etc. They are always searching for the “best” camera or lens. This is a losing proposition, as the most important part of your camera kit is you!
When you hear a discussion of the legendary players of any sport (Gretzky, Jordan, Ruth, Pele, etc.), I can guarantee you do not hear their success be attributed to their equipment. It is an atheletes ability to see the game, access to great coaching, and plenty of practice that allows them to elevate their game. The same holds true for photography.
A great lens will have advantages over a cheap lens, no question. But a great photograph has less to do with being tack sharp from edge to edge, and more to do with great composition, thought, and emotion. If you are in a position to upgrade your equipment, go for it. Though your time, energy, and resources are better spent investing in yourself. Developing your skills and eye as a photographer will always have a greater impact on your photography than a new lens will. Sit out a round or two of the camera wars and focus instead on yourself.