Not necessarily. A novice light heavyweight will be able to demolish a lightweight grandmaster titleholder. The lightweight won't be able to move the guy at all and any wrestling move he attempts will fail miserably. It's like bringing a .50cal gun to a tank fight.
Are we talking about boxing, still, or something else? I didn't know boxing had any kind of wrestling skill implied. Anyway, it depends on your definition of novice. Are we talking about novice, as in a low ranked professional, or novice, like somebody who fights at the local gym? Because if we are talking about pro boxers, I doubt any of them are below what would be, in DF, professional skill, and from there weight would matter in such close skill levels. If you really think you could get a local nobody to beat up a champion, though, that's pretty deluded. As for the 50.cal gun to the tank fight thing... aren't .50cal's only used as anti armor guns anyway?
The thing is, many lightweights think they are the shit because they have a black belt in _____. Of course it doesn't take them too long to realize that size really DOES matter in a fight, and it matters very much. As far as I'm concerned, you are one of the people yet to realize this. Get yourself in fight with someone bigger on purpose and post a video on youtube.
First off, I'm not a master. At all. I've studied Tae Kwon Do for a while (although I'm not doing it now) but I didn't get into too much of the practical stuff. Anyway, size will never be a substitute for skill, especially at higher levels, where, I've heard, you are taught techniques to bunch your muscles together in such a way that blows will have almost no impact on you no matter your opponents size. Especially with martial arts techniques that are specifically for larger opponents (judo, anybody) and the fact that a major facet of martial arts is to not only know how to fight, but also how to get around your bodies natural unconcious limiters on how much of your strength you use, size starts to matter less and less.
Let me rephrase that. I'm saying that being a master at your skill doesn't make you the master at fighting someone else of another skill. So in essense, if you'd want to make a more in-depth system, you'd have counter-jujitsu and counter-taekwondo skills. A legendary Muay Thai user that has proficient counter-taekwondo skills will wreck a legendary taekwondo user, providing that size is equal. (Dwarf vs huminz will be more complicated because dwarf has damblock +1 on the human)
That is interesting, actually. Of course, to be even more in depth, you would, instead of having "counter-X" skills, just figure out which martial arts styles lend themselves to beating other martial arts styles.