1.The changes of the dicciculty-setting doesn't make the enemys really weaker at the short turn.
They have fewer skills and may miss some cards but they still have their HP, their level and their basedeck.

2.Learning is a good skill if you can take it early. Having the advantage of the higher level gives you more HP, your ether raises faster and it delays the ether disturbance but you will miss those skillpoints at the early stages and on the long run you have to do many optional fights just to get 2-3 additional level ups during the campaign because of the exponential raising EP/Level. Still...i took learning everytime because i think the advantages outweight the disadvantage...but that is a matter of belive ;)

2If you're still at the 1. Mission and i remember right something is wrong if the enemy has the flying Walls and other flying creatures. After entering the city you should meet a Lev. 2 Hero with Aviaks, lesser unsummon and Supportspells and after the Viallage a Lev. 4 Hero with 3 different flying Walls, Hunger, unsummon and spells that delay you.

The first Hero should be easy prey and for the 2. Hero your attackspells are more important then your creatures.
You have Zap to attack Creatures and the enemy Hero and you should have that firespell that does more damage if you cast it with more ether.
Summon Rats, attack if you have more creatures then he has, use your buffs only directly before your attack.
Use your firespell to destroy the enemy Walls, spare your Zaps to attack the enemy Hero...attack the enemy creatures only if you can kill them with the Zap and you plan to use burning graves.
There was a building at the 1.Mission that strenghten your Zaps but i don't know anymore if you can reach before that fight against the Wallhero.

If this wasn't usefull, please leave a comment..then i will reinstall the game and replay the mission to revive my memory ;)