CapEx has a network of non-lawyer governance experts (directors, board advisors) who can serve as expert witnesses in D&O litigation. Here's an article about recent cases, published by NACD, an association every director should consider joining!
Delaware courts continue to apply (or refrain from applying) the Business Judgment Rule when judging director conduct. It's always a question of facts and circumstances, which vary from case to case. Bear in mind that Stephen Radin's book on the topic is more than 6,000 pages long. (No surprise that it is such a comprehensive work; Stephen is with Weil Gotshal, where the late, great Ira M. Millstein served, along with Holly Gregory back in the day. PS: I am grateful to NACD for publishing my work and enhancing it in the process.