A lot of the card choices in this seem like the anthology directed at people who want to play Historic Brawl or Arena Cube and not at people who want to play Explorer/Pioneer. There's nothing wrong with wanting to add cards to Arena for people who want to play these formats, but if that's what you want to do, you could put them in a separate anthology. Leave the Explorer Anthologies focused on getting Explorer closer to Pioneer.
Gates#78525
A lot of the card choices in this seem like the anthology directed at people who want to play Historic Brawl or Arena Cube and not at people who want to play Explorer/Pioneer. There's nothing wrong with wanting to add cards to Arena for people who want to play these formats, but if that's what you want to do, you could put them in a separate anthology. Leave the Explorer Anthologies focused on getting Explorer closer to Pioneer.