I write mostly classical or classically-oriented music, and to reiterate a point already made, the key to getting a realistic sound from orchestrations comes from mixing sample libraries.
How convincing your orchestrations will sound will often come down to whether or not you have the samples available that offer you the ability to create that sound. For example, if your woodwind arsenal consisted only of the GPO flutes, your ability to use them to realize any particular part is going to be limited by such things as:
1. the natural attack characteristic of its samples
2. how quickly the natural vibrato kicks in (if at all), and how wide the vibrato is
3. particular tonal character of the samples
4. release characteristics
5. how many articulations of that sound are available
So let's say you're trying to realize a fast staccatissimo part using the GPO flutes. They don't offer a staccato or staccatissimo articulation for flute, so your only choice is to use the straight "legato" flutes and see if would work. Well, chances are that the attack characteristic of that sound will be too "mushy" and the tonal character not bright enough. Maybe the release would be a little too long too.
Well, the release characteristic is adjustable by a parameter called "length". So you can tweak that, making it shorter, but the other inherent characteristics of the sound still won't be right. If you attempted to use this sound in your orchestration, the flutes won't speak well, and when heard on its own the part will be very "keyboardy" sounding.
The only solution is to have access to some other sample library that provides you with staccato/staccatissimo articulations. Or, as chance would have it, you might find that the non-staccato "normal" flute sounds offered by some other library would have a sharp enough attack to help you realize the part.
As an aside, most bassoon samples will let you play staccato and legato parts without having to change articulations. There is no rule saying that if you write staccato, portato, or tenuto that you must switch to staccato, portato, or tenuto-played samples. Sometimes the basic "normal" or "legato" version of a sample instrument will let you achieve realistic articulations (particularly note length) simply by keyboard playing technique.
But back to the flute. GPO offers a nice flutter-tongue articulation, but not samples of trills. Of course if you have the chops you can play in your trills with a normal legato flute sound. But again, depending on the tempo and style of the music, the notes may or may not speak correctly with any particuarly library's samples.
And what if you did have a library that contained flute trill samples. Would
those necessarily be played at the right speed to give you the effect you need? Maybe, maybe not.
Multiply these kinds of concerns by every instrument in the orchestra and you can quickly see why having access to a variety of sample libraries is essential.
So it's more about the libraries than the DAW. But one of the beautiful things about Logic is its ability to display the score of your work by (literally) pushing a button.
So yes, I'd recommend Logic. But more importantly, I'd recommend checking out (and being prepared to spend some $$$) on sample libraries. GPO is good for starters, but you'll quickly outgrow it as you start to realize its weaknesses. For me its strengths are in the woodwinds, harp, percussion instruments (some, not all), and some of the solo strings (the latter needing tons of EQ to make sound full). But string and horn ensembles are about as lame as they get.
Kirk Hunter's Emerald Collection is a tremendous value. Strings, brass, and woodwinds absolutely shine.