Constantly putting negative messages about Xf will not make anyone trust you more then today. Xenforo's login UI/X is not awkward , it is simply old. You can't compare a 6 year old design to a brand new developed design. It is not fair and i personally find single login/register options confusing by end users more. I tested this on many different websites with AB testing and on all my tests different login/signup resulted better experience.