DarthBo said:Redubbing will look fake.
it always does.
Dubbing Ewan to sound more like Alec is a bit too radical a change for me ;-)
Very little dialogue recorded on set or on location actually ends up in the majority movies so most of it is technically redubbed (including the Star Wars movies as they currently exist).
It might be interesting to see (or rather hear) someone attempt it, but I can imagine it going very wrong if done badly.