Hi there,
Not trying to discourage your quest -- always up for trying to learn -- but I wonder a few things when reviewing the initial post:
1. Can you read music at all? A little?
2. What is your goal in dumping the ensemble patches?
The second question, why have you set yourself this mission, I raise because I'm wondering if you are just trying to learn, or if you want to hire some real players to record some of your material, or if you just think you're 'supposed to' write that way?
If it's the latter "I ought to learn this" then that's kind of loaded. Most samples-only mockups sound pretty bad, honestly, so if you are getting pleasing results with an ensemble, I wouldn't change. I certainly wouldn't discard them altogether, but maybe start supplementing with individual instruments.
The Real Thing
Part of my reasoning is that a single cello or trumpet or viola is so absolutely amazing in what it can do. I had a single violin player last week (and actually later today, same player) and she brought magic, feeling, tenderness, wistfulness -- all of that from one player. The melody is fine but what she brought to it -- wow.
So what I'm getting at is that probably there is more great music discarded because people try to realise it with hideous, dull, poorly tuned, and simply lifeless samples. If only they had a string quartet or a few woodwinds or anything, some of that music would breathe and maybe go somewhere.
Consequently, if you're writing good-sounding material with the ensembles, don't toss them aside because you are "supposed to write like a real composer." I don't know if there are 20 composers alive today outside of media who get their pieces played by an orchestra any more, and even within media, how many get any time to rehearse, or anything you'd call a "proper" performance? Precious few.
So, don't do anything because someone implied or you assumed what you already are doing is "wrong."
And real performers are only a click away these days. Many soloists can record your piece at home and work that way.