An indoor, all year-round waterslide like what you describe would be a super-duper addition to the Weirs.
In all likelihood, nothing will be happening at the Weirs, and it will continue to be a seasonal area, open from Memorial Day to Labor Day for summer visitors, and all closed up for the remaining nine months. It is truly a great big waste of what could be a beautiful waterfront commercial area that attracts tourists all year round.
On the briter side of the Weirs....have you seen the big new construction now going on....just up the road....at
www.meredithbaynh.com