Unexpected Windfall is an okay card to play in treasure decks, or as a way to discard and draw, but nothing more
In most cases, its far better, and in a deck with three colors of mana, theres no doubt about that
DreamUp can help you create models even when you dont have a clear idea in mind or need inspiration
Bitterbloom Bearer is the modern, cracked evolution of that legendary engine, putting the same oppressive upkeep trigger onto a 1/1 Faerie Rogue body
Creatures you begin to control later in the turn won't gain any abilities, and the abilities gained won't change if creature cards enter or leave your graveyard after the ability has resolved
There are a LOT of ways to protect our creatures from Clot Sliver to Crystalline Sliver, ways to go over blockers with Winged Sliver, and ways to do enough damage like Megantic Sliver