From the sides and the edges of the Pyramid, we have the following classes and their general fields of excellence.

Class Might Elemental Self Path
Sorcerer ++  
Cleric  ++ 
Angel   ++
Paladin+ + 
Thief+  +
Druid ++ 
Shaman + +
Bard  ++

Path stands for Path of Life, of which the two best known examples are Light and Dark.
Tertiary classes such as Monk, Ranger, Pirate, Sage, Seer and Warrior, as well as magical creatures such as Dragon and Unicorn, may be available for hire to aid in specific quests.

Class First promotion Second promotion
Knight Champion First Knight
SorcererWizard Archmage
Cleric Priest High Priest
Angel Soul Warden Archangel / Prince of Darkness
Archer Marksman Elite Archer
Paladin Crusader Templar
Thief Trickster MageMaster Thief / Assassin
Druid Thaumaturge Great Druid
Shaman Witch Shaman Lord / Speaker of the Dead
Bard Minstrel Loremaster / Warmonger

Angels, Thieves, Shamans and Bards have to take a path (Light or Dark) at their second promotion.

Magic Fire Air Water Earth Spirit Mind Body Light Dark
Knight ---------
Cleric ----GGG--
Angel -------GG
Archer MMMM-----
Paladin ----MMM--
Thief -------MM
Shaman MMMM---MM
Bard ----MMMMM

Angels, Thieves, Shamans and Bards will loose all spellcasting abilities of the opposite path at their second promotion. Grandmastery can only be attained after the second promotion. Sorcerers, Clerics, Angels and Druids can become expert at all their magic skills before their first promotion, and master before their second. Archers, Paladins, Thieves, Shamans and Bards can become expert at their magic skills only after their first promtion, and master after their second.
Note that the Thief is somewhat different from the one in MM7. She is now a secondary class and can learn magic of the path of life, instead of just a little elemental magic as a more might-oriented tertiary class.

Combat Sword Axe Staff Spear Dagger Mace Music Bow Leather Chain Plate Shield
Cleric -EN--MEEEE-M
Angel M---E-MNEMEE
Archer EENME--GMG--
Thief M---GE-MGE-N
Druid --NNMEENE--E
Shaman -GNEE--NE---
Bard E-M---GNME--

Grandmastery can only be attained after the second promotion.

Miscellaneous Disarm Trap Percep tion Mer chant Medita tion Body building Identify Item Repair Identify Monster Arms master Alche my Diplo macy Stealth
Knight NNN-G-M-G-E-
Angel EM-MM-NGN-M-
Archer MMNEE-E-M--E
Paladin -NEEM-G-E-E-
Thief GEN-EM--EN-G
Shaman -GEMM--MNE--

Grandmastery can only be attained after the second promotion.