Empire Strikes Back says it all.
Lucas should have sticked to writing (kind of) and allowed rewrites by other writers to strengthen the dialogue.
Sorry but I always thought this argument was a lot of rubbish. I think Empire is better than a New hope, but it's not that much better in regards to it's directing, in fact, everything that's in empire acting wise is in a New Hope, as well as tone, style of editing, sfx(Lucas oversaw all the sfx sequences).
What did Irvin Kershner go on to direct? Robocop 2.
I can watch Robocop 2 as a trashy comicbook style movie, but it is not in the same league as the original. He never directed another one after Robo2.
There is a school of thought that both Lucas and coppola burned out filming a New Hope and Apocalypse Now respectively.
I think there is some truth to this, Lucas was under attack from all quarters during ANH, no-one believed in his movie apart from Alan Ladd, the guy who greenlit it. The actors, and the on set technicians, who would ignore Lucas' directions, made it a struggle for him to get things shot the way he wanted, often taking so much time that they would overun and then clock off. Not to mention all the groundbreaking sfx problems. Lucas was hospitilised with a breakdown towards the end of filming.
Anyone who has seen 'Hearts of Darkness' knows what a nightmare AN was for Coppola.
Lucas bowed out of directing and went into producing(until the prequels of course), while Coppola started working on smaller movies only, like the Outsiders and Rumble Fish.
Spileberg and Scorsese are the only two from that generation who still have a chance of making a good movie that can sit alongside the work from their prime. 'Catch me if you can' is probably the best Speilberg has done in a while. He rushed War of the worlds and kind of messed up Indy.
The departed is fine but is not up there with Scorsese's best crime flicks imo.