New York City landlords, developers, and real estate investors would gain if lower rates emerge from a planned overhaul of the city property tax system, but renters might not see long-term benefits.

That was among the takeaways from a panel of experts testifying Jan. 22 before the New York City Advisory Commission on Property Tax Reform, which is charged with recommending revenue-neutral changes to improve the fairness and transparency of the widely criticized system.

The commission, created in the spring by Mayor Bill de Blasio (D) and City Council Speaker Corey Johnson (D), is consulting with economists, law professors,...