I think it depends on how you're defining "freedom," as it's a bit subjective. I would say freedom is having the ability to play anything. It takes a tremendous amount of technical proficiency to play jazz with anything even loosely resembling freedom, so it's almost self-refuting to say that having technical proficiency is at odds with having freedom, if in fact freedom does mean having the ability to play anything--including things that require technical proficiency.
And are you really free when you play? You must stop and consider that for a moment. If I played an Altered chord, would you know what to play over it to sound good? How about an augmented or a diminished 13 chord? What if I played a progression that modulated through the circle of fifths, then went to a blues, then into a parallel dorian, then into melodic minor, before finally resolving back into a lydian groove? Could you keep up? Further, could you play well over all these changes with "emotion," dynamic, and proficiency the first time you ever heard them? And what if we were swinging all this in a 7/8 meter? Could you play in time?
Could you play totally out of key for an entire passage of a simple ii V I progression and still sound aesthetically pleasing?
Could you read a piece of music?
Could you write a piece of music down?
Now none of this means you're a good or bad player or musician, I am in no way implying that, but it does a have a lot to do with being free.
Whether you listen to music to hear pretty words, good drum beats, lyrics, emotions, or even technical proficiency, it's all still music; just because you don't like someone else's music doesn't make yours superior to theirs, and I also know you didn't say that, but a lot of guys dismiss jazz because they really don't understand music in general well enough to appreciate it's complexty and subtlety.
If the aforementioned definition of musical freedom is valid (able to play anything) then it follows only naturally that having the ability to play with said freedom requires a thorough understanding of harmonics, dissonances, and rhythm. This doesn't mean you have to know music theory, but I think it does mean you would have to be exceptionally gifted to play certain types of music without knowing at least a bit of it.
I would also disagree that blues is completely about "how" you play and not "what" you play. Though I do agree dynamics, phrasing, etc. are very important in blues, I would argue that such attributes are even more crucial in jazz music. Further, the seminal blues players of this century are all "guilty" as it were of "making the changes." You might ask what that means, what it specifically means is that these players change the notes, octave designations, etc. of the licks they play in specific relation to the harmony in the music. BB King, Albert King, Freddie King, Otis Rush, Albert Collins, T-Bone Walker (especially), Hendrix, SRV, and David Gilmore (also avid about playing the "right" notes) all play specific to the harmony of the music. So as far as notable music is concerned, I think it's almost a given that "what" is played serves equal significance in relation to "how" it is played.
In short, the best players play the right notes well.
