The WATE is a superb lens! I originally acquired this lens when there were no small/light options with the A7r. The range of 16-18-21 is great, particularly in a small package but comes at a premium!
There are technically sharper lenses with high micro contrast, but the WATE has the true Leica rendering less micro contrast, but still very sharp. I have made many large prints and combination of the A7r/A7rII sharpness with the WATE produces wonderful shots.
When the Loxia 21 arrived, I sold the WATE and I did regret it at the time. It is a lens that if you like the rendering and feel of the images, it is almost a must have
That said the Loxia 21 is a superb lens, and just different styles of rendering
