Personally I'd rather if every champ had a more common chance of play rather than "here's the standards!"
Sure, some champs MIGHT see play, but uh, to quote the Veigar/Lulu story in the main forums:
Ashe: "[To Veigar] Weren't you only chosen twice? And the one time you were chosen as a mage, none of the enemy team were mages"
Tl;Dr: most champs that DO see pick are troll picks and not to be competitive in the least. While they COULD be competitive, they just don't stand up versus any of the high priorities. It makes for a boring game when "Niche" is the excuse for "Competitively unviable".
Those niche picks won't be chosen when they won't be effective versus the competitives unless troll/random picks that even the users themselves can't explain WHY they went for them. Morde won't hold vs Renekton, Veigar won't hold vs Ziggs, Graves won't hold versus a Caitlyn (usually), and Jungle Maokai won't hold vs Lee Sin.