I used a Yveltal EX deck at regionals and performed very well. If I had won my last round, (ended in a tie and if I had more time I would have won) I had a chance at Top 8'ing with a 6-2 record but ties happen and I only made top 32. At MA, I thought it was a good play.
My Little Keldeo, don't most decks have bad match ups against toad? Flareon does after the toad player uses trump and Quaking Punch but that still made Top 8. I don't think there was a bad play. It also depends on who you face. I only played against one toad and no eggs.
Seattle Regionals:
Day 1 standings:
1st Place: Chase Moloney - Blastoise/Archies/BKEX
2nd Place: Tristen Cox
3rd Place: Oscar Morales
4th Place: Mia Violet (PokéBeach Translator!) - Toad/Dusknoir
5th Place: Millie Ramirez - Toad/Garb/Mewtwo
6th Place: Kian Amini
7th Place: Andrew Jackson
8th Place: Elijah Covitz
Day 2
1st: Chase Maloney - Darkrai/Yveltal/Archeops
2nd: Andrew Jackson - Landorus/Bats
3rd: Mia Violet - Toad/Dusknoir
~
7th - Millie Ramirez - Toad/Garb
8th - Tristin Cox - N/A (Did not show up)
There was a Flareon deck and a Manectric/BKEX in Day 2 as well, but I'm not sure who piloted what, exactly.