Matt Miller left Sequoia Capital last December and, like many longtime venture capitalists, chose to start his own fund. He didn’t, however, take the standard VC model with him.Instead, the London-based investor formed Evantic Capital with an unconventional structure. The new firm has raised more than $400 million with an eighth coming from backers that Miller calls “legends” — handpicked technology executives and investors who agreed to advise the startups Miller backs. In exchange, he plans to...