The racing calendar is from the 2009 f1 races. The developers are already looking into something similar to your suggestions. But at the moment they have other things that need to be prioritized.
And I expect ultra/hypersoft tyres would be pointless until tyres and wear are rebalanced--even if they suffered less than the typical nearly-doubling of wear they would wear 20-30% or more per lap, and run slower than hards in all but the coldest temperatures.
I think they should add Super Hard Tyres.
Developers needs to add 2019 calendar now its have no sense to add 2018 calendar in half 2018 season, because it was last Baku GP in 2019 its gonna be Miami GP.
Its only my opinion.