My CoM effective strategy

[WhiteMage]

why in your opinion Charismatic is so strong?

Hiring and buying items becomes cheap, but more importantly, most AIs stay at peace with me for a long time, so I can keep my number of wars low most of the time, and extend the number of spell trade events with them.

[GMBarak]

A few corrections:
1. choose: Blur, Phantom warriors, confusion, The reason is that you can send a cavalry to a Nagas node and each Phantom warriors will 70% kill a nagas unit, repeat until the node is clear of Nagas. also, 2 phantom warriors summon usually kills 1-2 air elementals each turn in a node. you can trade floating island from sorcery wizards you meet.
2. Better build order: market, magic market, stable, cavalryX2 or cavalryX3, the mana you accumulate while you wait for the cavalry to be ready can be used to clear nodes/capture cities.
3. first artifact to be built: +1 movement, pathfinding. according to the hero you get you build either or a wand bow with exorcise and possibly +1 movement depending on the situation.
Such a hero can clear great Lizards/Cockatrices, easy sorcery nodes, etc...
Focus on blocking enemy settlers from settling near you and blocking enemy stacks from taking your nodes/lairs.
Good luck!