This is why we have ice-out contests and everyone has an opinion.
My bet is that the ice pack is more fragile than some believe. Despite the cold nighttime temps and re-freezing, the water under the ice has been getting warmer, and therefore eating away from underneath.
I've also been watching the changes along my work commute. I travel Rt 495 from the Marlborough area to Andover. In the past week, most of the rivers, streams, and swamps have cleared completely of ice, and the few large ponds and lakes are showing signs of clearing. Another week should do it here, and this area is usually about 2 weeks ahead of the lakes.
A mid to 3rd week in April ice-out still sounds good to me.