Whoa. Why not just leave it up to the newspapers to figure it out based on reader feedback and other considerations?
Side note: I don't know if you are one of the numerous blogosphere Dowd-bashers, but she's been great lately. She's more like an editorial cartoonist or something but she really makes some poignant criticisms through her snyde snippy style.
Well, I'm not asking for legislation. Calling them "term limits" is just a nifty handle. Papers can do what they want, but varying their op-ed offerings sounds like a great idea to me.
As for Dowd, I'm not a basher mainly because I'm not a reader. I would expect a NY Times columnist to be a little more substantive, but I'll check out her latest offerings.
And Molly Ivins--I can't get enough of her! She'd definitely be an exception to the four-year rule.
Dowd's two greatest columns lately were (1) about our (this country's) short attention span---tied in to GW and (2) grooming/makeover advice to GW and his crew in the wake of him denouncing gay marriage. Both were really hilarious and hit home great points. Granted she's not that substantive but that's not her style. And people SO unfairly take her to task for her substantive "errors" when in reality that's not her deal. But she is IMO highly effective (judging from the small but inconsequential sample of people I have spoken to).
I actually like this idea a lot. Paul Krugman, for example, needs a cooling-off period lest his head explode in the middle of a diatribe, and he's increasingly predictable. And this coming from someone who almost always agrees.
I for one have thoroughly enjoyed Tom Friedman's columns over the past couple of years.