I asked Ludovic Beier why he plays Stradella (with slight mods) and he says he can play anything he wants on it and doesnt have the uncertainty of large jumps. And his playing certainly shows complete mastery.
If I were told I could only play Stradella, I really wouldn't have a problem with that. There are actually things you can do with Stradella by combining triads to form beautiful polychords that I envy. I think its biggest limitation is the fact that your voicings and inversions are inflexible. With free bass I have complete control over that, and for me, inversions are where its at.
You really don’t always want to be playing full chords with the left so Stradella’s inablity to produce sparse shells of just root/3 or root/7 is a limitation, particularly in groups, which is why you see a lot of players play RH only.
On both systems, the key to complexity of voicings, extensions, and alterations is the right hand.
For me, by using CBA-C on both sides I am more able to leverage the huge world of piano technique, including shell voicings, counterpoint, and additionally an overlap of notes that even pianists don’t have.
Its not just ‘free jazz’ that strays from vanilla ‘cycle of 5ths’ composition (Brazilian for example), and once you incorporate tritone substitutions, you’re again jumping all over the place with Stradella.