SiberianKhatru59
Does it have everything I need to get better at recording, mixing and mastering straight out of the box?
Therein lies the key. You can purchase a gazillion items of audio software in an effort to make your recordings perfect. Each will have its unique advantages, but most will fall into a standard category. If you do not learn how to use each basic category into which each plugin falls, then, owning a gazillion representatives of the category is not very useful.
If you have not mastered the use of the plugins that come with Platinum, then absolutely, there is everything you need in platinum to make yourself better. Maybe not everything you need to turn out the best state of the art recording that can come from any professional recording, mixing or mastering studio, or enough so that you can walk into such a studio and function without learning anything new, but enough to make your own efforts in these areas better than it is now. If you have mastered all the stuff that comes with Platinum, then you might need to look elsewhere for a challenge. You do not buy more stuff to make you better, you buy more stuff to make your product better, and until they invent a plug that fully automates the process, you will still have to learn the use of anything you buy. When you have exhausted the learning opportunities in SONAR...