"Eh Sexy Lady" is exactly what you will be saying when Narset, Enlightened Master enters the battlefield (Assuming you aren't near death and your opponent doesn't play a board wipe next turn - at which point you will probably just curl up in a ball and cry).
The beginning game uses a lot of burn to handle the field and deal direct damage to your opponent. Cards like Lightning Strike and Magma Jet will handle the early game (and sideboard burn cards based on the opponent's creature base)
Magma Jet will do a great job early game ensuring you draw what you need, and can assist in drawing the right colors of mana you will need.
Satyr Firedancer
combos great with burn spells so you can 2-for-1 the spell to you opponent and his creatures. A secondary purpose of
Satyr Firedancer
will be to draw out kill cards and burn spells early on to make way for the upcoming heavy hitters.
Jeskai Ascendancy is almost best played turn 3 over creatures for 2 huge reasons. On turn 4 you have the ability to cast multiple, to trigger card draw/discard. This will allow you to selectively choose what you need in your hand, and it also allows you to quickly add more instant spells to your graveyard.
When Spellheart Chimera drops turn 4 or 5, you should end up with a flyer of at least power 3 thanks to your burn spells. Mantis Rider is your second choice, as haste and vigilance are always nice.
Continually burn your opponent or creatures to boost Spellheart Chimera, deal more damage, and cycle through your deck for what you need. Jeskai Ascendancy will also be very helpful as it can get your flyers out of burn range of most spells by you casting your own burn in responce, triggering the +1/+1 to all creatures.
When Narset, Enlightened Master hits, game over. Other than a board wipe, your opponent will struggle to get her out of the way. You can almost always count on getting to cast at least 2 burn spells whenever she attacks, easily removing in blockers that go up against her.
Jeskai Ascendency
will also trigger, allowing you to boost Narset's defenses just in case.
Chandra, Pyromaster
is in this deck to help you get the little guys out of the way, but more importantly, trigger her 0 to help you go through more burn spells and build up the graveyard for Spellheart Chimera.
Sarkhan, the Dragonspeaker needs little explanation. His ability to become an 4/4 indestructible dragon will force you r opponent to choose where to send his flying/reaching blockers, if any.
I know this deck can definitely use some work, and the temples for mana may be excessive and slow it down. I have play tested it and love it, but I have yet to play against anyone or at an FNM to see how it really plays. I would love some feedback - still hesitant on the fact that most creatures on 3 drop or more.