I didn't think Welcome to Derry was "necessary" and it proved me wrong, not with how it impacted the IT movies but by telling a powerful story in its own right - the highlights of the series were the new Losers and the burning of The Black Spot. So... I'll remain optimistic about Season 2 pulling off something similar, and hope that it won't get too into the weeds of the potential time travel stuff, and... will probably regret it since so much of the finale was franchise-focused.