The objective for me is always to make a character I can enjoy for an entire campaign. Sometimes I intentionally play very weak characters, full of many aspects many others would consider "flaws in design". Some of the most fun I've ever had rping was playing weak characters that had to be resourceful and find ways to compensate for their low power. Other times I've played extremely powerful characters, if that's what I feel like at the time. Most of the time my characters fall somewhere in between. I never make a character with the goal of being the most powerful in the group. I always, always think a lot about my character's background and design him/her appropriately, even at the cost of character power.
On the topic of dump stats. That is one way of looking it at, another way is it doesn't make sense for certain characters to have a 3 Charisma. I just played through a Shadowrun campaign with a 1 in Charisma and it was a lot of fun rping a sociopath who was very unaware socially. I rp'ed her that way the entire campaign and it had a big impact on how others perceived her. It was a fun experience. In terms of character power, She was not min-maxed and I could have made her a lot more powerful if I wanted to. I stuck with her style the whole campaign and it was really a lot of fun. It really made me want to play a higher Charisma character next time, too. I don't feel there is anything wrong with having weaknesses, especially if the GM tries to model the game accordingly.
I'd say my rp group's biggest strength is focusing on the rp aspect of rpgs. We have extensive character histories, long opening stories or speeches to begin each session and sometimes multiple. We play a different kind of character every time and try to push our rp skills as far as we can go. We have had tons and tons of sessions with no combat and even play for more than 24 hours consecutively on some occasions. There are no hard and fast rules when creating characters. Just do what you like. I will just say this though, I personally feel you will have more fun if your character really comes to life and you make a big effort to get into the mindset of that character. Having a bunch of high stats can be fun for many players, sure, but really getting into character is where the greatest rp experiences can be had, that's just my opinion.
I don't think you need to optimize your characters, just do it if you feel like it. Do what you like at the time, that's the beauty of games like this. A lot of players on these boards say things like, "I ALWAYS take X piece of cyberware on my characters." Or, "I never play will Willpower lower than 3." Stuff like that is really not realistic. Sorry to step on anyone's toes but each person in the world is different and it's fun to rp those different personalities. There is no need to place restrictions on the design of your character! It's fun to explore all aspects of games and try a little of everything over time. Having big weaknesses can be just as fun as having big strengths, at least for my group. We try something new with every character, always trying to play new races, new qualities, new gear etc. We play like that in any rpg we play.
I'm not proof reading this so it's probably a bit scattered, but my general message is to just have fun doing what you like to do. Building all your characters with the ultimate goal of being as powerful as possible is a hollow experience for me, but if you like it, great, do it! I would only recommend you try it my way at least once because it can be a lot of fun.
This sub forum I have mixed feelings on. Part of me likes to come here to look at the characters people make. But another part of me doesn't like to see those characters picked apart by people that care nothing about the role playing aspects of the character. I constantly see advice like "This character should not use blades", and then the person that made the character goes ahead and takes that skill off their sheet in favor a more cookie cutter approach. This is especially bad when the character should have a skill like that, based on their character's history. I've had some of my characters picked apart for the most absurd reasons and always because my decisions were not "optimal". I never listen to advice like that, I'm here to have fun and play what I like, optimal or not. It's not like I don't understand how to min max, I just don't enjoy it.
Anyway, I'm repeating myself... just do what you like and try to have as much fun as possible. Trying new things can never hurt and being open minded is the first step to enhancing your role playing experience for yourself and everyone else at your table.