Death shrines spawn demons when constructed, but they do spawn them randomly throughout the game too. Is there an explanation for it?

In mage's tree there's a skill which gives +25% experience, how does it work? Is it similar to potential (btw, good job removing potential 2 and 3, they were quite forced choices when leveling)?

Are there more contents (like new monsters, champions, factions, items, quests) on the way or new patches will only be about balancing the game?

Also, spiders keep casting web on my archers, but there's no point in that. They should cast it on melee units, because they are the ones moving towards them.