A lot of people -- including John, who asked us about this by email -- are a little confused about what's happening to Arena Season 1 gear when Season 4 goes live on June 24th. Season 1 gear for honor is being replaced by Season 2 gear, but at the same time, Eyonix has posted to say that they don't have plans to switch around the PvE tokens for PvP gear system implemented with patch 2.4.
So wait, is Season 1 gear available during Season 4 or not? The answer is yes, but only from Tier 4 PvE tokens.
When season 3 went live, as you will remember, Season 1 gear went over to Honor, and bumped the old level 70 High Warlord and Grand Marshal gear completely off the vendors. You could not longer get it. Likewise, when Season 2 gear moves to honor, it will completely knock off the Season 1 gear from the honor vendors, and you will no longer be able to purchase it for honor.
However, if you have Tier 4 tokens, you'll still be able to head to the Isle of Quel'danas and turn them in for Season 1 Gladiator gear. If you want Season 2 Gladiator gear from PvE, you'll still have to turn in Tier 5 tokens from Serpentshrine Cavern and Tempest Keep. This might be Blizzard's attempt to keep the balance, although it seems like anyone with the ability to go take down Magtheridon for a Chestguard of the Fallen Hero could get Season 2 much easier and faster by grinding honor. It seems in this case that the dev team either felt that it wasn't worth it to go in and switch up the gear vendors or wanted to keep the amount of balance and challenge they implemented for the PvE token to PvP gear conversion.
So is Season 1 gear going away? In short, no. You'll not be able to buy it for honor anymore, but you will be able to buy it with Tier 4 tokens.