Played the archetype heavily in the past weeks. Here is the list i took to my pptq last week, and subsequently won with.
http://tappedout.net/mtg-decks/19-01-15-rg-beatdown/
Finished swiss in rank 1 after dropping only 1 game. Dropped another 1 in the top 8 to make 2 for the day.
Major Comments on your list:
13 three drops is WAY too many. Need to consolidate the slot to 10 or less. Fanatic isnt as explosive as a rabblemaster, but he guarantees ferocious the turn you play him. Cant overstate how important that is. Softens your vulnerability to drown, and is a key part of being able to beat other aggressive decks on the draw. Most times we cant afford to just race a /u/w heroic deck, or mono red. Fanatic is a key part of turning the tempo of the game. Never something i sb out, where rabble often is. Phoenix is a very resilient threat, but you cant cast it off a t1 elf unless you're taking points off confluence. Excellent vs control, otherwise its just worse than our other 3 drops.
Shaman turns our good draws into wins. Has synergy with every single 2 or 3 drop threat in my list. Downside is its variance. Where its good, it's outrageous. Where its bad, its embarrassing. Would never play more than 3. Its much more important to be able to play something beefy like poluk if the scenario calls for it. Chandra has quickly become a favorite in the list because of how frequently she gets the oh so delicate rabblemaster / shaman past what our opponent assumed was a sturdy defender.
Hammerhand has also been an unexpected all star. Not advocating more copies, and i did sb it out at times. But it has similar benefits to chandra (There is a huge primer on not getting blocked in this deck), can secure our board vs drown / anger, and creates an extra juicy god hand of t2 rabble, into t3 rabble, hammerhand it.