1. Warm slushy days can be every bit as good as a powder day. Bowls, wide open slopes can be just a blast in those conditions. I am a powder hound by nature, but I love the warm spring days, riding in a t shirt. Absolutely glorious.
2. You can get full on powder days in March. It's historically Colorado's snowiest month. Though the last 3 seasons have been a bit of a disappointment, we can get absolutely smoked. Four years ago Winterpark got over 80" out of one storm in March. It was amazing and set up the year for one of the strongest finishes I have seen. May 19th was a full on blower powder day in the backcountry that year. Over two feet deep with great coverage everywhere. It'll happen again.
3. What you are worried about is the windy, blustery, cold days with little snowfall. Especially after a warming trend. It turns everything to ice and in general it just sucks. Those are my most frequent ORD's (one run days) .
Overall the coverage is at it's best for the season in March. So it's a good month to bet on.