The best way to build an L2 is to lean into the L1's offerings (security, censorship resistance, proofs, data avail...) more, and reduce your logic to just being a sequencer and a prover (if based, just a prover) over the core execution. This is the combination of trust minimization and efficiency that the 2010s enterprise blockchain crew wanted, but was never able to achieve. Now, with Ethereum L2s, you can achieve it. And we've already seen successful examples of the L1's features protecting users' rights if something on the L2 goes wrong.