I'm not sure, the only thing I can think of is that maybe they're trying to save money for the new coaster, but even so, there are plenty of less popular rides they could close (Grand Prix, Eddie Stobart, junior Carousel etc.) rather than a popular family area, including one of the wooden coasters.
I think their gate figures have been lower so far this year, but with the poor start to the season that's no surprise really - and closing areas/rides an hour early isn't going to do much to improve this.
With that said, I have noticed some improvements to ride operations, and I hope that continues to get better.
As for construction, groundwork has started but actual coaster construction is very unlikely to be this year.