Currently, on the Dragonflight Beta, you won't reach Level 70 just by completing the campaign. You also need to run dungeons or complete side quests.
The first gating occurs in Azure Span where you need to be Level 66 to continue the Dragonflight campaign. However, you will be safe if you complete at least 3 dungeons at Level 60 and higher and you won't need to complete any side quests.
The second gating, however, is more noticeable and you will need to reach Level 70 to be able to start the final two chapters of the Dragonflight campaign.
Dragonflight includes a ton of side quests that you can easily find by opening the map for each zone and they reward you with reputation that increases your Renown with the main factions, so you would probably complete them anyway.
What do you think about gating the main campaign behind levels? Let us know your thoughts in the comments!
Source: News Latest Topics https://www.icy-veins.com/forums/topic/68632-level-70-needed-to-complete-final-2-chapters-of-the-dragonflight-campaign/