Beginner: 4 stroke honda
dunes: 4 stroke honda
ease of maintenance: 4 stroke honda
So in summary, buy her a 4 stroke honda! Go to the dealer, find a salesman who is willing to do a little talking then fill him in completely on the situation. If he keeps pushing a big bike, tell him he's an asshat and walk to the next salesman, lather, rinse repeat. You may hafta do this a few times before getting somebody who understands, but this is your wife's well being we're talking about, so safety and fitment go hand in hand.
I completely agree on the 200cc range too. If she's about 5'7" or less, the 230 is probably the biggest she'll feel comfortable on, but if she's taller then you may consider the crf 250 enduro version. It'll have many of the characteristics and handling of a 125 2 stroke, but will feel torquier and have a much broader powerband. Also, don't let people mess you up with the term powerband. Many people believe it's what happens when a 2 stroke hits the pipe, but every engine has a powerband, being from it's lowest rpm to redline.
Don't overlook used for her first bike either. She's going to be dropping it more than usual, so an already beat bike that runs well will offer a far lesser loss the more she drops it. If you do look at a used bike for her, I'd strongly recommend the xr200. Very well built and dead reliable. If you really really wanna get her a 2 stroke with good manners though, kawisaki kdx200 all the way!