some plugins have these features designed in, but not all do, and there are quiet a few plugins that don’t that I would love to be able to use on stereo channels on either side, or dual mono by taking up two insert slots with one assigned left, and one assigned right.
it would make the task of stereo balance correcting much easier.
Thanks
This has bin possible for a long time. I ofthen use this function my self.
Open the channel editor window.
At the bottom of the insert slot, you will see routing option. Open it.
Now you can set the routing to mono for the plugins and flip them left or right channel, at your will.
Can this be done in DOP?
Yes, split the stereo channel.
Rest is just a visual mind block 
It is not possible in dop. Only the standard option of splitting the stereo to 2 mono channels. Wich is the superior option as far as having full signal control.
Might be a future request to get some simple insert routing for dop.
But I think a lot of users, just go for the superior option of split and full control. 
It creates a lot of steps to split and then interleave if it is stereo samples you are editing and want to keep them stereo, but yea I’m doing it the way you suggested.
Yes, it is a few extra steps. But with a few key commands, setting up the link menu, save presets, it will quickly speed things up.
In my younger days, when I was new to all of this. A old enginer said to me “there is only one stereo channel, and thats the master bus” pointing at the console and the L and R master faders. 
I think you should just put a solved on this thread and make a new one. Ask for dop insert routing on stereo sources.
I can give you a +1 on that. 
I changed the title, thanks for the help
+1