The area allocation
Blizzard's October 1 Beta development notes raised the playable cap to Level 30. These 11-point Mage routes preserve the initial Level 20 snapshot, and no Level 30 allocation is verified here. Official source: https://us.forums.blizzard.com/en/wow/t/wow-forever-beta-development-notes-%E2%80%93-updated-october-1/2360696
Improved Frostbolt 5, Ice Shards 3, Improved Frost Nova 2 and Improved Blizzard 1. This Level 20 allocation differs from the Frost single-target route: it gives up two Ice Shards ranks and one Piercing Ice rank for two Improved Frost Nova ranks and one Improved Blizzard rank. This reviewed Level 20 starter allocation spends 11 points. Blizzard raised the playable Beta cap to Level 30 on October 1; this route is not a reviewed Level 30 build.
Spend order
Improved Frostbolt first — five points, and enough to open the second row. Ice Shards to three ranks next. Improved Frost Nova ranks after that, and Improved Blizzard last: it needs ten Frost points spent before the tree will let you take it, which is exactly what the first three steps provide.
Spells this route leans on
This allocation selects Improved Frost Nova and Improved Blizzard; it does not verify when the underlying spells are learned. The reviewed 69913 selected-rank text reduces Frost Nova’s cooldown by 4 sec and adds a Blizzard Chill that slows movement by 15% for 1.5 sec. Improved Frostbolt has published cast-time reduction text, but the talent catalogue is not a Mage spellbook or a verified combat rotation.
Replay the area tradeoff
Load the area preset, then compare it with the single-target preset. The first eight points match. The final three change from two Ice Shards points and one Piercing Ice point to two Improved Frost Nova points and one Improved Blizzard point. Copy the resulting allocation only after checking that the calculator still shows eleven points.