I know people have discussed tabbed plugins, or having plugins in the lowerzone.
But another, and possibly better solution would just be a Reason style rack in which all insert plugins are combined into as one window.
If you click on an individual insert plugin on the channel to view it, it brings up the entire rack of all plugins on that channel, but skips to the one you selected.
There could be different options, like, ‘Insert Rack follows channel selection’ so that the insert rack automatically changes to which ever channel you select. This way, you could leave the “VST Insert Rack” window on another computer screen and always see all or most the plugins instantly for each channel you select.
Select multiple channels could add additional racks horizontally side by side, and or, automatically create tabs for each of the multiple selected channels.
My reason for suggesting this is avoiding VST standard complications making plugins fit and look good in tabbed lowerzone and all the bugs and problems this would probably create for VST developers needing to update their plugins code and stuff.