You should give it a try. It wasnt all that horrible. I missed two whole days because of vacations, but still got final prize without gemming. As long as you search for opponents that are ranked higher, and have 2 units that can charge bb by 2nd turn, it's pretty much a free event.
For wood event, I'm certain if you have Ophelia and/or Zelnite, it will be easy to get final prize.
My team: Ophelia x 3, Dilma, Zelnite
They need to make the exclusive unit more worthwhile. Months ago when they first attempted the Thunder Vortex, mono and rainbow teams were still being used by players and Felneus was one of the top leaders. And even then the Thunder and Fire unit's leader skill was just "ok".