My 3 month sabbatical given to me by my most former employer was wonderful, but detrimental to the employer.
It unwound all the foolishness at work for me and couldnt do it anymore with a straight face. It also showed me I could ER with no problems.
As someone who interviewed probably thousands of people and hired hundreds, a sabbatical gap wouldnt have made me blink an eye. But I'm probably not your average interviewer. That someone had the motivation to get off the hampster wheel for a while as far as I'm concerned would be a plus. I *did* interview one candidate who confessed that she had to take a few years off to get some psychological work done and later found out she threatened the lives of several of her co-workers and smashed the place up when they fired her. I didnt think that was a real positive.
The thing is, the only change a sabbatical makes is removing you from day to day politics and high volume, high detail day to day interaction with specific tools, techniques and data related to your profession. These things are very easily learned and/or updated. You as a worker and person probably dont change much as far as your work habits, the way you deal with people and projects, etc. Its very easy to teach a new technique, tool or set of statistics or characteristics. Its almost impossible to make someone stop being a dick, work better with other people or become an effective employee.
If a company couldnt look past a sabbatical, considering it detrimental, then I wouldnt want to work for them. Now a 10+ year gap might give me pause, but I'd hire a former VP of something with a 10 year gap into a senior position...not necessarily a VP job...and look at them to advance back into the executive ranks. I might not hire someone who wrote code 10 years ago for a new coding job. Besides, I'd get sick and tired of hearing how the programming languages "way back then" were better than they are today...
I also dont think its necessary to jump right back in where you left off. I figure I could get a moderate level job in marketing, sales, IT or engineering in a heartbeat. Someone would take a chance on their $70k a year to see if I still "had it". I figure it'd take me a year, maybe two in a big company, before I was offered a management job and five before I was right back where I started from.
Heaven forbid!