Holm has had 10 MMA fights spanned over 6 years in one of the top MMA schools in the world.Her takedown defense was the key and it was highly technical.Mayweather is not going to get that takedown defense skill in months.Additionally, Mayweather is a boxer.He is dangerous in one range and that is the same range as the clinching range. Holm was dangerous with kicks and knees which adds a whole new dimension of attacks. I know you guys don't see what I see but understand that my opinion is not from the viewpoint of some fan.I actually compete in Grappling at one of the top MMA gyms in the US. I've seen professional boxers come and spar MMA. They get taken down by whitebelts. It takes alot of skill to avoid takedowns,avoid the clinch,and change your boxing stance to not get taken down.Ronda Rousey is not going to try and stand with that dude. She is going to take him down and armbar him very easily.
If interested, here is a really good video explaining how technical Holm's takedown defense was.It took 6 years of Holm training at a top MMA gym and having 9 fights to get this skill.Mayweather is just not going to get this skill in a few months just because he is a talented boxer.