I had this idea in mind for a long time. hopefuly it might be sticky with the contribution of other members and it will be a detailed guide for star wars fan editors.

From visual and aesthetic pov i will try to contribute and then you can add or fix some of the comparisons. Im not here for the story so dont mess this list :)

I read in an article the subconscious power of the average time per shot. OT has very different times compare with PT.
The establishing shots in OT are most of the time static mattes with minimalistic characteristics from rendering pov. We might have some pseudo 2d zoom in some of them. In PT we have fancy 3d camera projected mattes with intense eye candy elements. Camera traveling and turn around above several establishing shots is a common fact in PT.
Some establishing shots of the interiors in OT have most of the shots centered perspective rather angled and wide like PT
The colors in OT are far more simpler and natural. Based on real locations the color pallete is calm and more grounded. PT has over saturated colors that brings life and helps better the blending/alien look.
OT have simpler colored moods from PT. In a way PT forces you get emotional involved under carefully placed colors and tones.
OT keeps the ship engines minimalistic as possible. Only lights with colored glows. In PT tried to define it that is more like fuel with an in-engine animation and subtle flames.
We never see an engine starts or turn down in OT. In PT we see it many times.
Lasers and lightsabers in OT doent create interactive lightning with their environment. In PT from AOTC and later each Clone and most of the Jedi have their own muzzle flash/saber clash light on their body or on their environment.
Apart Leia's hologram we never seen again from where a hologram was emitting with the standard definition of holo emitter. In PT defines every source or holographic projection apart some jedi temple shots.
In OT we see rare use of holographic display shots. They use monitors mostly. In PT we get a constant use of hologram even in the smallest things. They use some monitors too.
In OT blasters cause a smoke mess each time they muzzle or hit something. Making the environment a big foggy mess. In PT except some parts of TPM the blasters seems to create a burn mark or just a black scorch mark in the walls. Sometimes we have intense sparks tho.
OT have enough set/real sounds in the final mix making it more grounded. In PT most of the sound mix was made from scratch.
Music follows the character with its own theme in OT. For example in ANH calm tones for tattoine and marching/industrial music for death star. Music defines characters/plot/action and locations. In PT we might get some nice examples of new themes but they was not used in the proper way of showing and not hiding something that is more memorable. TMP has the best score in PT because is mostly original. The later 2 movies had ripped of its music.
There is no continuity to lightsabers or lasers in both sagas.
OT is focused to the characters and careful placement of the camera to hide missing or incomplete sets. PT extends and open up everything/lose the contact from the characters.
In OT everything big will be showed close as possible to the actors. Scale will not preveal in OT. Less is more maybe. In PT large scales are everywhere. humans are tiny next to everything.
Rare use of Landing or taking of sequences in OT compare with the all the time ones in PT.
OT have very simple planet designs from space pov. PT have colorful planets with their own atmosphere animation.
OT have no Sun(s) visible from space shots/flybys/battles.PT have it all the time.
OT have its space shots almost black and white apart the lasers. In PT we get glimpses or color on ships (blue/cyan)
Force fields in OT are white with no energy shield effect that defines a "door". PT shows that the fields are blue/cyan with the energy effect.
OT have a good memorable designs/ships. PT not only manage to copy OT but even the retro designs of mcquarrie were lost in messy sequences
OT doenst have almost nowhere the "shaky camera" effect. PT uses that all the time.
Shields are invisible in OT. In PT we get many tastes of how how a shield looks like. Even that is on a ship or ground.
The camera animation is too static in OT. Compare the fluid impossible movement in PT.
OT have no glass effect on the ship's cockpits. PT tones that more. Generally what was left out unexplained in OT PT tries to make them more real. (dont know if they succeed it)
In OT the force was used for.

Mind trick,
chocking,
training,
force passing,
Pulling,
Meditation,
Levitating,
Jumping,
Deflecting,
Lightning,
saber throwing
Sense.

In PT the force was used for.

Deflect,
Pushing,
Speed,
Mind trick,
Cheat,
Jump,
Sense,
Lightning,
Choking,
Levitating,
Saber throwing
Meditation,
Force passing

In OT we have no choir in music a few small themes in ESB and ROTJ. PT have Choir in their themes more often.
In OT we dont see Children. In PT we see Children all the time.
In OT designs everything has something rusty and greebled surface. In PT everything is rounded and flat (with few exceptions)
In OT we see the extended star-field effect when a ship enters to hyperspace. In PT we dont. No spinning star-fields either.
In OT there are only grounded droids. In PT we see that they can hover/fly
The star-fields in OT (except ROTJ) is black and white. In PT it has mostly bluish hues. Also in PT the star-field have some haze/trembling effect sometimes.
Many shots of a flyby is cut in two parts in OT. In PT we see one shot followed by CG camera, achieving that effect.
In OT we see several Violence and blood. In ANH we see the burned bodies/skeletons and a bloody arm. In ESB Blood from luke's face(spit too) ROTJ we see Han's hands are in blood after looking leia's wound. In PT there is Violence too but it was never discribed with blood.
In OT every episode includes a physical torture scene. In PT We can assume there is only emotional torture.
In OT the engine sound in cockpit shots are more visible from OT. Sometimes in PT the mix is so intense that you lose that feeling of interior sound.

-Angel