Clip editing efficiency: How can I do this with 15?
 
I want to be able to edit like in s8.5  without lanes and filters.
 
I want to see, and be able to edit, without changing to a different "smart" tool:
  transients
  envelopes
  clip positions
  clip editing
 
I can do all of these things in 8.5 without constantly repeating two extra clicks, or having to remember which control key is the right key to temporarily switch to another "smart" tool.
 
What am I missing?

I may be misunderstanding your question but it seems to me that you have defaulted to manually choosing the desired tools as you go. There is but one 'smart' tool which is represented by the star icon in the tools bar (which can be accessed by pressing 'T'). While using the smart tool its icon and function will change depending on your cursors position. Example: hover your cursor over the right edge of a clip and the tool will change to the 'size' or 'stretch' function icon.
https://www.cakewalk.com/Documentation?product=SONAR%20X3&language=3&help=Tools.04.html

I don't think you can do envelopes but the smart tool does let you do fades and stretches and such.

Btw if anyone happens to know the key commands to switch between clips, envelopes and transient markers I'd like that!

Switching between clips and envelopes can be accomplished using Shift+Click on each object.   Also, Shift+Right-click works to alternate between the last two selected objects.
 

I thank you all for your responses.
 
I was hoping s15 was more smarter. Doing all of what I listed in 8.5 should be available in X and 15. But,.....
 
From my perspective, changing "filters" is the equivalent to changing tools.
 
Having to use key commands is the equivalent of changing tools. 
 
Nothing is smart about having to manually change the tool.