As of November’22, a lot of improvements done this year
- bootstrapping is now running smoothly, after few fixes
- mainnet 5.0 activation will happen in few days, will increase block capacity by like 5-10x
- mempool protection done in recent releases, now the node is pulling transactions it can realistically process between blocks. After 5.0 we can continue work on protecting mempool from possible spam issues and avoiding script recalculation when it is not needed (by introducing transaction classes , see Protecting mempool from computationally heavy transactions )
And right now I am working on bootstrapping with UTXO set snapshot and then NiPoPoWs. That would mean ultra-fast bootstrapping with the same security guarantees as processing all the blocks since genesis, for nodes with fresh wallets. After stabilized implementation being released, miners can be asked about rising block limits again.
As a parallel effort, it is proper time to start 6.0 features planning, including scalability improvements.