It's a shame that the fresh off the production line Y-Wings only appear in The Clone Wars animated show but they would still be a design from the last days of the war.
Concorde still looks like the future now and that was a product of sixties engineering and is now obsolete.
As for the compositional language there in lies a multitude of problems.
The Rebellion seen in the OT is a coalition of many groups with largely customised out of date hardware, running a series of guerrilla campaigns against a single uniform, well equipped navy.
The two forces of the PT have both got up to date hardware and are fighting large scale battles against each other.
If the PT is a World War the OT is more a series of bushfire skirmishes.
That is going to dictate a different visual language.
The Bantha in the room is obviously that the two film series were created decades apart.
It is arguable that making a film set (not that long) in the past of the same fictional universe but with larger scale battles would create stylistic problems even if the technology being used to make them was the same.
If anything the OT looks more epic which in a way is all wrong considering the nature of the conflicts described in the story.
RLM is correct in pointing out that the PT is a film series made by a mostly seated director about characters who are mostly seated.
The larger scale war of the PT lacks any of the emotional and visual impact of the smaller scale war of the OT.
If you look at the WWI battle scenes in The Young Indiana Jones Chronicles you get a better idea of what the PT could have been like with more modern techniques.
Love or hate the series those scenes really did feel like a war and not like a cartoon, as much because the audience had time to connect to the characters as the sequences were depictions of a real life tragedy.
However the characters were certainly more kinetic than in the PT and in a more realistic fashion when they were.
The fisticuffs in the PT felt more like dancing than fighting and having battles between duplicate men and duplicate robots didn't cook up much of an emotional connection with this viewer.