I am not a fan of just putting the foot down. I am not talking about being linear v. rotational as a philosophy (so please don't start an argument), but the kids with that no stride style tend to over-rotate, and pull the ball. The bat leaves the zone too early, and they 'fall' on their heels sometimes. They have trouble with curve balls and outside pitches.
I like them to have more extension towards center field, more plate coverage, and be freer with the front foot. You would never play tennis and say, 'don't move that front foot' to hit the ball. I am not saying move it all over the place, but there is freedom to the swing if the foot is lifted slightly, or brought from open to even (or picked up with a high leg kick, as you see in college, although don't recommend that for young ones). She is almost trying to lift it! They also tend to be better at getting to low pitches if freer. Me personally, I can't time my swing with that style, it feels like I am weakly throwing the bat, so I don't know how they do it...
We have tried to get her to stride but she had a tendency to overstride, looking like she was almost in a split and it threw her timing off. I know her front leg load looks weird and we have had gotten other coaches to look at it and they pretty much say that it is fine, while it is not the idea way, it works for her. While she have no problems with the curve or outside pitches, I do see her struggle with the low pitches. If a strike goes by her, it is the low pitches or a change up. As far as batting goes, she only struckout twice the entire JV season but a high percentage of them didn't make it out of infield.