When looking at evenness of sound it becomes quite obvious that the consistency of our impact pressure, articulated beginning of our tone, is a big part of this.
With this in mind, I have also noticed a trend toward less variety of articulation in the quest for evenness. Also, basic note lengths are longer than lets say 30 years ago.
I remember when I studied with Ron Ricketts of the Minnesota Orchestra in the mid to late 1960's, that he was very into short playing especially for faster passages. This was a style of trombone playing, John Swallow also did this to an extent as well, that was prominent and I think often times players associated short note lengths and firm pointed articulations with clarity.
This changed for me when I started to take with Steven Zellmer who wanted there to be more substance and body on any note regardless of whether it was fast or slow in tempo or length. I soon realized that clarity had to do with the synchronization of air, lip vibration and tongue, coming together for an immediate impact of sound, not the hardness of the attack or the note length. With that said, I noticed that the players who can get very 'evenness of sound finicky', do not warm to real short pecky staccato or do not necessarily use a large variety of articulation themselves.
What is interesting, is that many of my favorite string players who are soloists, have an incredible spectrum of articulation and tone colors that if expressed on a brass instrument would cause many of the brass and wind players of the symphonic world to shudder. What is wrong with variety? I think players might think that they need to master the one even quality sound first, and then after that they will have enough control to venture into other colors because they will actually have the control to do it deliberately. My thoughts on that will have to wait until my next post on this subject! Hmmm.....