[Suggestion] Since town buildings have an opportunity cost (build time), what about tactical spells having an incr. Mana/Action Point opp. cost?

Why? Casting a spell already costs an action point, giving it a casting time of x turns is both boring and severely unbalanced to spellcasting, since a sword doesn't take x turns to swing.

Although a sword doesn't have range.  If bows are rebalanced so they aren't all powerful any more (either reduced damage or higher action point cost or both), it would be good for ranged spell attacks to also be rebalanced to have a higher action point cost or mana point cost.

Btw: are there any "activate on melee attack" or "cast on particular weapon" spells currently in 0.92?

Best regards,
Steven.

It also doesn't cost mana to swing! Are we going to keep going like this?

I think that the casting time makes still sense. But this should be reserved for higher tier spells which could cause a lot of damage or effects several tiles at once. Simple firebolts should be casted instantly Alot of games utilize such a behaviour to be able to counter them