A few thoughts.
First off, a budget deck can be moderately competitive and might even take an FNM here or there, but is unlikely to perform well against top-end competition. Sadly the expensive cards are expensive because, well, they're good.
Second, Brimaz, despite not really finding a home in many decks, will hold his value for a bit after rotation (if not increasing) as his EDH (and tiny leaders) appeal remains and the supply drops even further. Additionally, I was thinking as a 2x or MAYBE 3x, but you wouldn't want to run 4x of him anyway. I would say a 2-2 split between him and spear.
Third, your decisions to relegate cards to the sideboard strike me as strange. The sideboard isn't meant to put cards 61 - 75 that we wanted to play but just couldn't find room. You should use the sideboard to contain cards that will significantly increase your chances in a given matchup. So, for instance, green decks will likely be packing 2x
Gaea's Revenge to face down control decks in the coming months. While the card is pretty good normally, it might not fit the style of the deck. BUT, when facing down a control player, if you're running green, you would be hard pressed to find a better option. This in mind, if you want to run spear or dictate, find slots for them in the main. Otherwise, I don't know that there's a matchup that you would realistically need more pumps to suddenly become favored.