The time to reach level 20 is on average around twelve hours, compared to a much longer and more volatile time to reach the cap on Live. This does not mean that leveling slowed down though. No longer will players out-level a story just because they did some side-quests, or a few queues. This means we could better message new power unlocks in the quest rewards, and ensure a proper pace and challenge as you work through each zone. As you play through the new leveling flow, you achieve new levels at key milestones in the stories of each zone. The big change with Module 21 is an alignment to Dungeons & Dragons with an adjusted level cap of 20.
As such, a new level cap is being instituted in Neverwinter come Module 21, squishing levels to a new cap of 20. Cryptic details exactly why the level squish is coming in Neverwinter, specifically stating the goal is to 'streamline leveling' in order to get players to content the team is pumping out faster.