Until recently they weren't even advertised, being a surprise extra for the buyer to discover
Either way, this is a powerful mono-green commander if youre the type of player that likes having tricks up their sleeve
Tinker is ridiculous, but also doesn't fit the Wizard theme at all
If the rules allowed both sides of the card to give you access to the cards the other had exiled, I might be more excited about these two being on the field together but as I understand it they don't work that way
Darkness Approaches asked for two cards from your hand as cost, but it didn't change the battle position of the Monster
For just five mana, Arvad gives you a 3/3 creature with two solid keywords, and, more importantly, a +2/+2 boost to all your other legendary creatures in play