Yes I know what you mean. It is a lot of controls that have to be managed. I have ended up doing things in a simplified way so I don't have to think about anything but the music. You can get endlessly involved in the technique, since VSL allows almost infinite possibilites. Someone else probably sets things up completely differently and just as well, but I have recently been trying, in my attempts at simplifying, to have only keyswitches for articulations, and not CCs such as mod for articulations themselves. That is different from what I suggested for the sul/legato crossfade. But I stopped using that approach actually for the same reason you are talking about - that there are two many things being controlled by different controllers. So by keeping articulations controlled by keyswitch, and other things such as volume, expression, crossfade by CCs , you get a "feel" for the mod wheel (or other controller) as something active and evolving that is done to the more stable keyswitched articulation.
I must admit I always make up my own matrices and presets because I want to have a feel for everything from the ground up. So they don't use all the options of the programming that is within the factory presets. What I have also been doing is trying to create matrices that are uniform across the orchestra as much as possible and are the same in structure for all the instrument, so I get used to where the keyswitches are. Examples of these cells horizontally and vertically (with a lot of empty spaces available) are -
1st violins:
legato; sustain; detache; staccato; sforzando; tremolo; trill 1; trill 2.
sul or portamento legato
divisi sustain; detache; staccato; etc. as needed (next smaller ensemble with volume adjustment such as splitting Orchestral strings into Chamber, Chamber STrings into solos, Appassionata strings into Orchestral - the numbers don't match exactly but sound almost perfect)
solo violin:
legato; sustain; detache; staccato; dynamic (long); dymanic (medium); dynamic (short); sforzando; forte piano
sul legato
So with this system, you start with the "longest" notes - the totally connected ones, progress left to right to sustain but freshly attacked, then shorter and shorter note values, then less often used articulations. And when you find you need something more, you can just add it to this basic structure at the end. By using the horizontal cell switch, you then have all the slots below for the same kind of sound but varied, such as sul legato instead of regular, or divisi sustain instead of full ensemble. This might seem insane, but in practice once it is set up it becomes familiar and very useable.
I then have been applying to this basic structure mod wheel for controlling crossfade amount, and (believe it or not) pitch wheel for turning on or off crossfade. The reason I do this is that the pitch wheel I never use for actual pitch adjustment, since that sounds horrible, and so it is a free controller. Since you want a readily accessable controller, the pitch wheel is right there on every keyboard. So if you set up the matrix or preset to respond to pitch wheel pressed down means crossfade, and mod wheel crossfade amount, it is very easy to ctonrl and totally separate from all those articulation controls. I have also created a basic template in my sequencer which has at the first measure zeroing of all these controllers to their proper initial settings so they are not inadvertantly left on or off.
It seems you always have to add more than velocity crossfade, so that adds one more layer that has to be dealt with and that is the Expression CC11 which I just write or paint in within the sequencer. But that is pretty easy and fun to do once you have everything else basically in place.
This may be a crazy system but like you I have wanted to concentrate on the music and not have the programming be in the way while working on it. So once you have a setup such as this, though it may be some programming to first create it becomes much easier to use in practice.
