After a huge year-to-date rally, the risk-reward hinges on execution and whether the new playbook can translate into sustained profitability.Opendoor Technologies (OPEN 14.46%), the e-commerce platform for buying and selling homes, just staged one of the market's loudest leadership resets. The company named Kaz Nejatian, formerly Shopify's chief operating officer, as CEO and said it is going into "founder mode" as co-founders Keith Rabois and Eric Wu rejoined the board. The announcement ignited another shar ...