Sure!

1. I have been considering this too: the five damage earlier would often be quite useful, but I find that this deck does not have too many issues dealing with single creatures as we have Ratify, Epiphany, etc. Wyrmbreath does give us some more damage from our hand, potentially 10 more, but its hard to say whether its worth it. I would like to add that it is quite rare that you get the combo with the Morgana's: my epiphanies usually used as removal, and sometimes just thrown to face if nothing is going on. The card draw from Epiphany is super clutch, and it gives us an answer to Giant Pangolin (!!) and Guild Enforcer (!), whereas Wyrmbreath does not.

2. I would definitely buy a Monolith of Storms, insanse synergy with this deck and sort of fills the Wyrmbreath role which you were seeking: can be used for clearing, but also as 7-9-11 damage to face occasionally. Sick card, but not really used otherwise. There are a couple of other legendaries as well: from the top of my head I can imagine the 'final draft' guy could be quite useful. I would also switch out the Basilisk for an Iron-tooth, as that is a much better removal card. There might be something better, but from the cards that I've seen, these are my first concerns.