The biggest open decentralization gap in Ethereum scaling.
A sequencer orders transactions before they’re posted to Ethereum. In 2026 every major L2 still runs a single one — usually the team or its backer — which means temporary censorship or downtime risk, even though forced-exit guarantees protect your funds. Shared sequencing (Espresso, Flashbots) is the leading fix, targeted for mainnet around 2026–2027.
Centralized sequencers are the main thing standing between today’s Stage 1 rollups and a fully decentralized Stage 2.