I am of the following opinions.
1. 6 copies of SoFr are best. You want the highest possible chance of drawing one, because you want to get 4 out ASAP for dat guaranteed added damage / immune creatures. Plus you never know if a few are going to get stolen/deflagged. In all the testing I've done so far, I've never found a SoFr to be a dead card in my hand.
2. While the wee bit of damage from the damsel's is nice, I honestly find that I would prefer a pillar whenever I draw one. It doesn't SEEM like there should be that much of a quanta difference, but I feel like I can play my wyrms/SoFr faster when using the no damsels version.
3. This new SoFr version is a tad slower, but with untargetable creatures with momentum, I believe it'd be well suited for arena. Assuming the new SoFr remains as it is now in the trainer, this deck will be marvelous for bronze/silver.