I disagree. My company is a 100% remote workforce, and identifying standouts isn't terribly difficult. I would argue that the fact that everyone is working remotely makes the entire process much more objective, as you don't fall into the standard judgement traps that are well known in face to face interactions. When I'm trying to decide whether a team member should be moved into a team lead role, I'm evaluating them solely on their communication skills, code quality (by looking at commit history), and their effectiveness during meetings. I don't honestly feel like I miss anything by not having onsite interactions.