Big changes are coming later this year to The Elder Scrolls Online in the form of One Tamriel, an overhaul of the Zenimax MMO that Director Matt Firor said will “make it easier for ESO players to group together, and to promote the sense of freedom to explore that Elder Scrolls games are known for.” The plan, in a nutshell, is to remove all content barriers from the game and make everything available to everyone.
When One Tamriel goes live, character levels will be scaled for the full game in the same way that they're currently scaled to the Imperial City, Orsinium, Thieves Guild, and Dark Brotherhood DLC zones. You'll be able to take on the entirety of Tamriel however you wish—“Just walk across the world and you will always find appropriately leveled content”—and, aside from PvP, players will be able to group and play with whoever they want, regardless of level or allegiance.
PvE Alliance restrictions are also being dropped, and “silver” and “gold” versions of zones will be replaced by Cadwell quest storylines that can be completed in any order. Trials and Dungeons will continue to offer Standard and Veteran difficulties, and the Coldharbour zone will be inaccessible to players who haven't finished the questline that leads there; if you're invited to join a group that's already there, however, you'll be able to access it immediately.
“In general, higher level players will be the same 'level' as lower level players, but they will have far more tools in their arsenal: better gear, more abilities, and of course more Champion points,” Firor wrote. “We will adjust gear rewards to scale appropriately to make sure that there is always a way to get more powerful via crafting, questing, PvP, and dungeon/trial boss loot drops.”
More information about One Tamriel will be announced over the summer and leading up to its launch, currently slated for sometime this autumn.