The reason that older translations render Nephilim (and also Rephaim, which only causes confusion) as giant is that they follow the LXX which rendered Nephilim (and also Rephaim and giborrim) as gigantes which means earth-born and implies nothing about height. FYI: I recently published a book titled, "Nephilim and Giants as per Pop-Researchers" which is a comprehensive consideration of the claims of I.D.E. Thomas, Chuck Missler, Dante Fortson, Derek Gilbert, Brian Godawa, Patrick Heron, Thomas Horn, Ken Johnson, L.A. Marzulli, Josh Peck, CK Quarterman, Steve Quayle, Rob Skiba, Gary Wayne, Jim Wilhelmsen, et al.: www.truefreethinker.com/articles/new-book-%E2%80%9Cnephilim-and-giants-pop-researchers%E2%80%9D