It is a video game, the whole bunch of simetrical maps seems totally unlikely but hey, that is the only way to have a balanced gameplay.
As for the helmets, there was a debate amongst the devs: some wanted to use glyphs (or enchantments i am not really sure of the name used).
Glyphs allowed the stacking without problem but at the end, the devs decided to go for the equipement in order to make things easier for the newbie (if i want to have more mana, i buy an helm, more hp an armor.....).
Just cope with it, it is just a game. I don't see why i would receive 2 golds each time i kill a minotaur, but that is just how things are in this game.
Aha, thank you for the explanation.
But in my mind, as a newbie, it wasn't "easier" at all, because intuitively, I would never had considered trying to buy two weapons or two armors, because of fear that I would loose the first one. It wasn't until I heard from other players that you could do that, that I tried it.
So, at least to me, glyphs would have made more sense. There could have been "combat glyphs", "mana glyphs" and "special glyphs" or something, if they wanted to make understandeable categories.