As a middle viewpoint, i might say that my cheap mu43 zoom lenses have challenged me to include busy backgrounds in a pleasing way. I came from the Canon world, and my favorite setup was a 3 prime lens setup with 300f4, 100f2, and 40f2.8. The 100f2 and 300f4 lenses gave beautiful background blur, i could make images work with very busy backgrounds, i could ignore the background if i wanted. Now, my 100 at f5.6 or 300 at f6.3 makes it much more challenging to ignore the background, and it has taken time to learn to view the scene as a whole rather than just looking at the primary subject.
Being a hobbyist, i could afford the time to learn and maneuver over many days to get different framings. I think I take better images now because of it, i like the somewhat environmental portrait it gives me, and adds another tool. But i miss the tools of the 100f2 and 300f4, i cannot make those images with my current kit. I enjoy a challenge though, so I'm not ready to invest in more kit just yet. But if i tried to sell photos, i wouldn't hesitate to upgrade.