We should stop thinking about L2s as literally being "branded shards" of Ethereum, with the social status and responsibilities that this entails. Instead, we can think of L2s as being a full spectrum, which includes both chains backed by the full faith and credit of Ethereum with various unique properties (eg. not just EVM), as well as a whole array of options at different levels of connection to Ethereum, that each person (or bot) is free to care about or not care about depending on their needs.
What would I do today if I were an L2?
* Identify a value add other than "scaling". Examples: (i) non-EVM specialized features/VMs around privacy, (ii) efficiency specialized around a particular application, (iii) truly extreme levels of scaling that even a greatly expanded L1 will not do, (iv) a totally different design for non-financial applications, eg. social, identity, AI, (v) ultra-low-latency and other sequencing properties, (vi) maybe built-in oracles or decentralized dispute resolution or other "non-computationally-verifiable" features
* Be stage 1 at the minimum (otherwise you really are just a separate L1 with a bridge, and you should just call yourself that) if you're doing things with ETH or other ethereum-issued assets
* Support maximum interoperability with Ethereum, though this will differ for each one (eg. what if you're not EVM, or even not financial?)
From Ethereum's side, over the past few months I've become more convinced of the value of the native rollup precompile, particuarly once we have enshrined ZK-EVM proofs that we need anyway to scale L1. This is a precompile that verifies a ZK-EVM proof, and it's "part of Ethereum", so (i) it auto-upgrades along with Ethereum, and (ii) if the precompile has a bug, Ethereum will hard-fork to fix the bug.
