But my reasons are that you don't need to build around Artarka or Silumgar's abilities for them to be good there color scheme already will have you doing most of that due to they nature as those colors Kologan and Dromoka need a it of a work around but you still don't need to build a entire deck around them for them to work
Trynn & Silvar allow you to play tribal, hatebears, Voltron, aggro, tokens, and aristocrats all in the same deck and it plays them all very well
Feel free to snag a copy at current retail if you need it, but theres no need to rush
Hakamo-o can be obtained from Celestial Guardians: Lunala pack in the Celestial Guardians set
What do you think about The Ruinous Powers precon
Like Ritual Monsters, there are restrictions such as being able to Special Summon only by ritual summoning