WoW Forever is changing Classic PvP ranks, and the grind is very different
Blizzard explains the new Honor system, weekly rank caps, PvP gear upgrades, and seasonal Legacy rewards.

World of Warcraft: Forever is reworking one of Classic WoW's most notorious grinds: PvP ranks. The familiar titles, from Private and Scout to Grand Marshal and High Warlord, are returning, but you will not have to compete against your entire server to climb the ladder.
We now have more details about the system, including how Honor works, Rank Points, gear, and seasonal rewards. Blizzard wants to keep the spirit of Classic PvP and give players a more predictable way to progress, regardless of how much time they can spend in battlegrounds. The information we managed to gather comes from Blizzard's official post and from the video by Creator Neviriah. You can check her video out for even more details:
Wow Forever Replaces the Old PvP Ranking Grind
In original WoW, ranking was a competition against other players on your server. Your weekly progress depended on your Honor relative to everyone else's, making the climb to Rank 14 a demanding commitment that could punish you for slowing down. You will have two separate progression tracks called Honor and Rank Points.
Honor is a currency you can spend to buy PvP gear and other rewards, and Rank Points determine your progress toward the next rank. Spending Honor on equipment will not block your rank progression.
There is also a weekly limit on how far you can rank up, because Rank 14 will not be available from week one.
Rank 3 is available in the first week
Rank 5 is available in the second week
Rank 11 becomes available in Week 7
Rank 14 should unlock in Week 10
So basically everyone can reach the same rank at the same time, even if you do not play for 48h straight, but this information comes from the current game data and could change before launch. The only issue is that ranks reset with each patch cycle, so reaching Rank 14 is not really permanent. Your Legacy progression, however, carries over.
PvP Gear Upgrade Path
The new ranking system also changes how players acquire PvP equipment. Both blue-quality and epic-quality gear sets can be purchased with Honor, but the epic versions require the corresponding blue item and an Emboldened Seal. These seals have rank requirements, so you have a reason to keep climbing even after you get your initial gear.
Rank 1 - Tabard
Rank 2 - PvP Trinket
Rank 3 - Cloaks
Rank 4 - Necklace
Rank 5 - Combat Potions
Rank 6 - Tabard
Rank 7 - Battle Standard
Rank 8 - Epic Bracers/Epic Belt Upgrade Token
Rank 9 - Epic Boots Upgrade Token
Rank 10 - Epic Gloves Upgrade Token
Rank 11 - Mounts
Rank 12 - Epic Legs/Epic Shoulders Upgrade Token
Rank 13 - Epic Chest/Epic Helm Upgrade Token
Rank 14 - Epic Weapons
Keep in mind that no, you do not need to earn a high rank just to start gearing up. The blue-quality pieces are available from the beginning. The ranks just determine when you can get the upgrade seals for their epic versions.
You can check your current rank, Rank Points, and available rewards through the PvP tab in your Character Pane.

Battlegrounds Offer More Ways to Progress
WoW Forever brings back familiar battlegrounds but also introduces Darkspear Islands, a new 15-versus-15 map inspired by The Burning Crusade's Eye of the Storm.
The battleground features four bases to capture and a central flag. Holding bases generates points over time, and carrying the flag to a controlled base earns additional points. Controlling more bases also increases the value of delivering the flag.
Darkspear Islands comes with two new reputations:
The Theramore Expeditionary Force for the Alliance
The Darkspear Raiders for the Horde
You can earn rewards such as trinkets, rings, weapons, and armor through these factions.
Right now, these are the battlegrounds we know of:
Warsong Gulch: 10 versus 10, available from level 10
Arathi Basin: 10 versus 10, Available from level 20
Darkspear Islands: 15 versus 15, available from level 30
Alterac Valley: 40 versus 40, available from level 51

Battlegrounds can even bring together players from different Forever rulesets, but not Hardcore characters.
There are also hints that PvP could expand further. The game files contain references to a Battle for Gilneas battleground and an arena map called Hyjal Crater and Mak'gora Arena. Blizzard has not officially announced these features, so they could be placeholders or content intended for a later update.
For now, WoW Forever's revamped ranking system and new battleground give PvP players a better progression path to look forward to, without requiring them to spend every waking hour fighting for a place on the leaderboard.
