>Whats the key to creating excellent heroes (battle wise)
Give them custom abilities that the player will enjoy using, otherwise I don't know how to answer this question
>What exactly is the secret to creating good elite units (I've seen you have some experience with this)
Specify what purpose the elite unit serves, then pick out abilities suited for that purpose, balance out the unit, also all elite units should have Resistant skin, and maybe a tweaked elune's grace to reduce damage from spells and magic (Otherwise I've seen players easily beat them by spamming spells)
>Which type of aerial units do you prefer to give the player and why
If you give the player any aerial unit that costs less than 3 food it will get spammed heavily, so I tend to give the player air units that are strong but have a higher food cost (gryphons, dragons etc.) If the player has 100 food at his disposal, with 5 going to workers in the mine, and another 5 going to lumber workers, the player wont be able to spam aerial units that cost 5 or 6 food while maintaining some kind of a standing army
>How many heroes should the player get to control in a typical mission
Varies by mission, but usually at least 2 heroes, and usually those 2 complement each other, in some missions I would give as many as five heroes but the enemy would also have a good number of heroes to counter this
>Defense vs offense, what should be stronger, should the player get excellent offensive units or defensive
This depends on how you want your mission to go, too much offensive stuff and the mission usually ends fast, if the enemy has high defenses compared to the player's offensive capacity then the mission will be long (and I tend to like this)
>How to make missions really enjoyable
Add good music, mid mission cinematics, plot twists, etc. Look at other highly rated campaigns
>What types of items do you prefer to give heroes
Ok I didn't really give my hero items, I can recall giving them an orb item to make sure they can attack air units but that was it, I would recommend giving heroes some healing items, look at other campaigns
>Ways to control difficulty
Hundreds of ways to do this, too numerous to list on here, look at other campaigns
>How many missions do you think a good campaign should have
Anywhere from 5 to 18 or whatever the largest number of missions which can be put in a campaign