Goblins of Destiny (Pioneer)

When I discovered that Door of Destinies was in Pioneer, I just had to make a list that made use of them, and I thought that Goblins would be a fun tribe to build a deck with.
The idea of the deck is to, well, cast a bunch of goblins and kill the opponent with them.
As for the goblins themselves, there were just too many good goblins around, so there's a lot of room for everyone to make whatever adjustments they want.
As for me, my choices were:

On the 1drop slot, Legion Loyalist brings a lot of value when you swing with many many goblins by giving them tramole and first strike, plus tokens can't block them in that scenario, while Skirk Prospector is a great source of ramp to throw our big goblins/artifacts.
On the 2drops, Goblin Piledriver is just so strong in a goblin deck, growing inmensely when attacking with other goblins AND it has protection from blue, which is pretty nice (don't know if it dodges counters though), while Mardu Scout, the card with by far the heaviest competition for a slot, is there because it's Dash ability lets us cast it again and again to keep triggering Vanquisher's Banner and Door of Destinies every turn.
The 3 drops also had a lot of competition, Krenko, Tin Street Kingpin was an obvious choice, since it's a ridiculous source of goblins and works very well with the Door. Legion Warboss is another source of Goblin tokens, and it has Mentor which helps grow our army, while Goblin Warchief makes our goblins cheaper which helps when we have one of our artifacts in play.
On the 4drops, we have the star of the deck, Door of Destinies, as well as some of our most powerful goblins. The door powers up our goblins inmensely, Goblin Ringleader helps us look for more Goblins and Goblin Trashmaster not only serves as yet another anthem effect, but it doubles as Artifact hate.
And on our 5drop slot, we have our trusty Vanquisher's Banner, a slow card to be sure but very powerful in our deck, as it both powers our goblins and it draws as cards to throw more goblins.

As for the manabase, we use 21 lands to make space for the many important cards in our deck. There were precious few lands with interesting effects that aren't too expensive, so we play what we get. $ copies of Castle Embereth for that little extra power, Ramunap Ruins helps shocking our opponent and, while a tapland, Memorial to War gives us a little Land hate to kill special lands if it comes to that.

The sideboard is where I feel this deck really falls short. I just don't know what to put in there, so I would request of anyone with the knowledge and will to help to give suggestions. Thank you