It seemed like Domitian lowered the money supply by increasing silver purity for coins. I can not say if that is a good or bad thing. It would keep prices stable but limit growth.

While Domitian does seemed to have increased expenses by building roads, rebuilding Rome and providing welfare and entertainment for Romans, he didn't add more territory. Not adding territory for plundering restrained economic growth in Rome.

In general, Roman civilization depended heavily on slavery, a command economy, and plundering. Without more lands to exploit, Rome would stagnate.