The next big thing for Parachains is asynchronous backing. It will allow parachains to build blocks concurrently with the relay chain and hence bring back the block time from 12s to 6s.
One other difference to a standalone chain is that parachains only allow for 0.5s of execution time (block weight) as opposed to 2s for a standalone chain. Will this limitation also be lifted by asynchronous backing?
It remains to be seen exactly by how much, but this is one of the main goals of asynchronous backing. By adding more pipelining to the parachains protocol, more execution time can be allocated to each block. The parachains protocol only reasons about resources in terms of execution time and PoV size per block, but increases in either should map closely to increases in Substrate weight.
Yes it should increase the available block execution time. These 0.5s where chosen by me to fit into the 2 seconds we have to build, send and validate the block. We already currently see that we don't fit into these 2 seconds because networking is for example too slow. With asynchronous backing we should hopefully be able to lift all of these restrictions to allow bigger blocks :)
