Yeah, this is going to work. Let's look at just the first level spells.
Abora (Green): Minor - Charm Person, Detect Poison and Disease, Expeditious Retreat, Fog Cloud, Hail of Thorns, Longstrider. Major - Animal Friendship, Ensnaring Strike, Entangle, Goodberry, Hunter's Mark, Speak with Animals.
Valra (Yellow): Minor - Alarm, Command, Heroism, Mage Armor, Purify Food and Drink, Shield. Major - Bless, Cure Wounds, Divine Favor, Healing Word, Sanctuary, Shield of Faith
Balcra (Blue): Minor - Comprehend Languages, Create or Destroy Water, Detect Magic, Disguise Self, Jump, Silent Image. Major - Color Spray, Feather Fall, Indentify, Illusory Script, Knock, Sleep.
Sodra (Purple): Minor - False Life, Grease, Inflict Wounds, Ray of Sickness, Unseen Servant, Wrathful Smite. Major - Bane, Armor of Agathys, Arms of Hadar, Duress, Dissonant Whispers, Hex
Shunra (Red): Minor - Compelled Duel, Faerie Fire, Quick, Reaching Weapon, Searing Smite, Thunderous Smite. Major - Burning Hands, Guiding Bolt, Hellish Rebuke, Magic Missile, Thunderwave, Witch Bolt
Repeating from the previous post - Bards have access Abora & Balcra. Clerics access Valra & Sodra. Druids access Abora & Valra. Warlocks access Shunra & Sodra and Wizards access Shunra & Balcra. Take a look at the lists above and see how much that changes these classes spell selections.
Sorcerers must have half their known spells match their alignment, whatever that is. The other half of their spell complement is comprised of the minor access spells of any color they choose.
Bards secret lore ability is still able to pluck spells from anywhere. A bard who picks the college of valor picks up minor access to Valra. A bard who picks the college of lore picks up minor access to Sodra. A new bard college will be made themed on Shunra and picking up minor access to her spells. Name suggestions for the college are welcome.
Clerics may pick up minor access to a color as determined by their path or god, or they will pick up some minor power to compensate for a reduced range of spell selection. Clerics who's ethos blocks them from actually using one more more spells from their home colors may be allowed to pick up a major. Overall this class may prove to be the trickiest to re-balance.
Druids of the moon pick up minor access to balcra, and druids of the land pick up minor access to shunra. "Golgari" druids, with minor access to Sodra, are coming.
Warlocks of the "old one" pick up minor access to balcra, warlocks of the fey pick up minor access to abora. Fiend warlocks need a small new power to compensate for a loss of access to spells. A new pact must be made for Valra
Wizards... oh boy. Wizards have access to all the spells of their school that are minor access. At the same levels that bards learn secrets the school wizards may learn one spell of their school regardless of color access restrictions.
Or... A wizard can forgo school specialization to pick up major access to a third color and minor access to the remaining two. Spells of the minor colors are considered one level higher than they actually are for these wizards.
As a draft, does this sound balanced?