Rocky,
It isn't just the additional 6 feet in length, although that did have some impact. The Apache is significantly wider than the Cobra and weighs considerably more as well. Through the years, the AH-1 has maintained that same basic slim head-on view, making it a relatively small target. With an Apache coming at you, you're usually well aware of it, even if you are quaking in your boots!
The Marines also insisted on retaining the TOW capability, something that the Army wanted nothing to do with once the Apache was chosen. That's one reason our Marine Corps brethren try to say the Cobra is a "more capable" platform.
It still has to hover to taxi....