Regarding implants, stat bonuses from them can actually be found on other items as well, meaning that points could be devoted to other stats. Another thing is that your personal crystal can easily supply you with + bonuses to stats including attributes like Wisdom, Strength and Dexterity and these increase as your PC levels up to a maximum level of 40+.
For skills, Repair and Persuade are basic ones that you will find useful throughout K2. Others are ones that characters like Kreia and Bao-Dur already have.
There is no Jedi class that is necessarily superior to others, but is based on what you like.
Finding crystals might be hard in K2, as items are randomly generated, but would not worry much about that as you will likely find at least 3 or more and Nar Shadda's item dealers will carry some of them. Some lightsaber items are crafted based on skills, so part of damage will come from such upgrade items.