"Resistance and Tactics are also two essential skills that will be useful for both a warrior and a mage." - I can't agree with that...
Well, Logistics, although it increases the number of moves, only gives a bonus to them on the road, so I think that Logistics without Pathfinding is not very effective.
So, you took "Fire"... I'm willing to bet that you never use the "Wall of Fire" spell, am I right? - It has saved me many times... And you can list the advantages of "Fire" for a very long time...;)
But regarding:
I will immediately say that there were never any stupid or useless skills in Heroes 3!!!
And skills such as Navigation, Mysticism, Pathfinding, Diplomacy - also become useless in some tournaments!!!