Well, the thing to keep in mind here is that that article was written to give people a guide for gaining mass. Typically, people aren’t trying to get bigger abs.
Now, once you get up to advanced progressions, then yes there will innately be a strong core component, especially with levers and advanced bridge progressions. But, at the more basic level, I still recommend focusing on things like planks, hanging leg raises, and L sits.
Yeah dude, there’s nothing wrong with skipping ahead or working out more frequently as long as you don’t injure yourself…but you will almost always know when you’re pushing yourself too hard, and a serious injury is, the vast majority of the time, predicated by a minor strain or a touch of tendinitis; there are warning signs.
Keep in mind that anything you read in CC, or anywhere else, is not dogma, it’s just a suggestion. Coach Wade wrote CC as a guide to training under the general conditions of incarceration. So yeah, if you’ve got a nice 10 or 15 year chunk of time to focus primarily on your training, then sure, stretch it out. Get the most out of each exercise so that you will get bigger. Take your time working up to the biggest moves to keep it interesting for longer. But there’s no reason to walk if you want to run…as long as you are ready to run.
There are always further skills to challenge you, so don’t worry about that. Figure out where you would ultimately like to be with your training, and train for that. If you are set on getting muscle ups but don’t see yourself going for one arm pull ups, then it doesn’t make the most sense to train for one arm pull ups. Conversely, if you want to get the one arm pull up, training for muscle ups isn’t the fastest way to get there, nor is getting really good at 2 arm pull ups (although if you were really good at pull ups and muscle ups then one arm pull ups might be the next step for you).
Also, CC is a good book and everything, but I like it more for the training philosophies and such conjecture it presents. A lot of the intermediate exercises I don’t find to be the most practical and/or fun route. As for exercises leading up to the big moves, I much prefer the information presented in Al’s books Raising The Bar and Pushing The Limits