Moltres is a defining part of the metagame, because one of its major flaws is Stealth Rock, so if seen in team preview, the biggest priority is to set up Stealth Rock. The help with this weakness Rapid Spinners are more prevalent, and there lies the biggest problem.
Using Moltres almost entails having a Rapid Spinner on the team, which could take up valuable space, so in essence when using Moltres, you're actually using two Pokemon. Often is usually Kabutops or Cryogonal, but right now Kabutops is the top fossil, as it is much harder to spin block, Cofagrigus is gone, and can revenge Nidoqueen and opposing Moltres.
In general, this offensive oriented metagame does give Moltres less 'safe' chances to switch in, especially against offensive teams, which try to set up Stealth Rock as soon as possible and hit fast and hard. However, Moltres shines against more balanced and stall teams, the latter more so when utilizing Substitute, as it can switch in with less risk as well as outspeed the opposition and hit hard.
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