There have been a couple of interesting posts recently on Leon Schlesinger, the founder and producer of Looney Tunes and Merrie Melodies. Amid Amidi has a good post on why Schlesinger was the Best Executive Ever, and Mark Evanier has an equally good post qualifying Amid's praise (Schlesinger gave his artists lots of freedom, but not much money).
I can't add much to the discussion except that I don't think Amid is quite right to say that Schlesinger wasn't one of those executives who "insist on putting their 'personal stamp' on everything that gets produced." Or, at least, despite Schlesinger's general willingness to leave his artists alone, he did put his personal stamp on the cartoons, in the sense that the kinds of cartoons the studio made were very reflective of his own personal taste. Bob Clampett goes into this a bit in the documentary "The Boys From Termite Terrace" (included on the first Looney Tunes DVD set), where he mentions that some elements of the WB cartoon style developed because Schlesinger liked a fast pace, big punchlines followed by an iris-out -- he liked funny cartoons and he encouraged his staff to pack their cartoons with gags.
There's a famous story that after Chuck Jones had been a director for several years, mostly making slow-paced faux-Disney cartoons, Schlesinger called him in and ordered him to "make funny cartoons like Clampett's" or he'd be fired (which might explain why Jones was the only WB director to consistently badmouth Schlesinger in interviews). Assuming this or something like it happened, that's a clear-cut case of executive interference: the big Philistine executive calls the idealistic young director in and tells him to stop making his dream projects and make something more commercial. We don't think of it as executive interference because nobody ever seems to remember the times when interference makes things better. (Jean Renoir, asked whether he resented the interference of producers, replied that, no, "I like interference. It promotes discussion, and discussion often improves your work.") But Schlesinger had a house style and he wanted people to stick to it and not just do their own thing. Now, that house style was developed in part by letting people like Tex Avery and Bob Clampett and Chuck Jones experiment and do their own thing, but once that style was set, nobody had so much freedom that he could just decide to abandon it and try something entirely different.
However, I'm not saying that interference always makes cartoons better or that Schlesinger interfered as much as today's executives. The new breed of TV/movie executive often tends to be someone who believes, without any justification, that he or she is a creative force in the making of the films or shows; that's why a lot of their changes are nit-picky things that don't really make any commercial sense, but do make sense in terms of their overall "vision" for a work they believe to be their own. The Schlesinger type of executive, by contrast, doesn't pretend that the work is his (at least while it's being made; after it's finished, he hogs all the credit in public); he just wants the artists to stick to making the kind of stuff he likes. And the crassly commercial executive, who wants to make money and keep the theatre distributors happy, is generally all right too, even if he'll sometimes gut a project to suit the prevailing commercial trends. It's the sensitive, artistic executive that you've got to watch out for.