The number one aspect we look for in any planeswalker is the ability to protect itself on the board, usually either by creating tokens or by making it harder for your opponent to attack into it
This suggests that the deck will be stocked with hero cards, and it will be supported by either equipment to further increase the damage output of the creatures, or instants and sorceries to help maintain a strong board presence while keeping your opponents' boards light
From the distance I can hear them still complaining about Prophet of Kruphix for a little while longer, but it quickly settles back to chat about Magic in general, just without me included
When Tiamat enters the battlefield, if you cast it, search your library for up to five Dragon cards not named Tiamat that each have different names, reveal them, put them into your hand, then shuffle