Even if you were to try and adhere to the minim note value that Chopin had written, it wouldn't seem smart to me to try and do so with the fingers - the pedal is there for particularly this reason. One of the elements of technique that this Etude helps with is the pivotal motion of the wrist. This is why every editor that I know of has chosen a fingering that enhances this movement, knowing that the E-flat is easily maintained by the pedal. I don't have my Ekier edition handy, but I believe Ekier uses this fingering and says that it comes from Chopin himself (someone correct me on this if I'm wrong). Ultimately, playing this E-flat with a 3, puts my large hand (and I suspect most people would agree) under a great deal of strain if I try to play the octave to E-flat above it and even more strain if I try to play the A-flat as well. This type of tension in the hand is absolutely not conducive to a free, rotating wrist.
To understand Chopin's notation, I would suggest you think about this passage orchestrally. I would imagine that whatever strings provide the harmony in this fictitious orchestration (almost certainly with a pizzicato double-bass on the lowest A-flat) would be accompanied by horns with this E-flat, which is essentially another voice in this texture.
I cannot say this without having heard you play, but I should imagine that you will find it difficult to achieve the smoothness and control that is required of the left hand in this Etude, if you try to use a different finger on the E-flat.