Regarding "awesome" character builds that provide the ultimate offense or defense, it strikes me that a lot of people are missing two key points.
1) Combat is now an opposed activity. As such, it depends on opponents of relatively balanced skill in order to provide balanced results.
Example: Say your character has Agility 3, Pistols 2 and a Smartlink. That's 7 dice. If you're shooting at even a basic security guard you're going to have a tough time of it should there be any negative modifiers to your attack. On the other hand, if you're shooting a guy in a wheelchair with a Reaction of 1 and a Body of 1 you'll hit every time and maybe even single shot him. You need a fairly large amount of negative modifiers to give the poor guy even a chance at survival.
In conclusion - it's not how powerful your character is. It's how much more powerful than his opponent your character is. Should there be a significant spread, one side or the other will always win. This is either a bug or a feature, depending upon your preference.
2) There is a great deal of variance in the dice system. We've all been working on the assumption that you'll get one hit for every three dice thrown. In the long run, that is very true. However, on any given roll you may see a hit on every other die or even two hits out of every three dice thrown or you may see a hit for every 5 dice thrown. Luck is a major factor in how many hits you get.
Example: Take the character with the 12 Reaction. Over the long run (thousands of rolls, say) he'll average 4 hits on his defense tests. But its not unlikely for him to have two or three on a bad roll. These rolls will occur a significant fraction of the time. In those cases, he's no better defended than a guy with a 9 or even a 6 reaction. (Although at times he'll be better defended, of course). Even the guy with 24 pistols can expect to be generating only 5 or 6 hits a significant fraction of the time. While that won't stop him from wounding, it may cause him to wound when he critically needs to kill.
Mr. 24 may be a dangerous guy (and popular with the ladies), but he shouldn't get cocky - nothing in the Sixth World is guaranteed.