Typically there are two types of offenses, a vertical one, and a horizontal one.
Vertical Offenses
These are offenses that want to move the ball forward. Offensively to move the ball forward you are taking a path of greatest resistence. Everything has to be bigger in a vertical offense. The linemen are larger because the purpose is to have an advantage moving forward. A vertical offense is about physicality not finesse. The running backs tend to be bigger because the offense requires the ability to run downhill and take a pounding. The tight ends are bigger as well as the wide receivers in order to have advantages over safeties and linebackers in blocking.
Horizontal Offenses
These offenses are about space and timing. This puts a priority on athleticism and agility. The lineman are required to cover more ground so the tend to be smaller. The linemen have to block in zones, so speed to get there is more important than power that is required in a vertical offense. The running backs have to be quick and have ability to change direction, so size isn't as important as speed is. Receivers need to be quicker and more explosive off the line. In turn the receivers tend to be smaller, because smaller people tend to be quicker.
Vertical Offense
The Quarterback fits in based on skill set. In a vertical offense the goal for a QB is to beat a defense over the top. The size of the offense is important in order to force the defense close to the line of scrimmage. The bigger the line the better chances are that they can handle one on one inline blocking. Then it becomes a numbers game that can force the defense to compensate with the aid of a safety. Size and speed (different than quickness) of the wide receiver is important, because the throws have a larger margin of error primarily because of distance. The Raiders, Steelers, Ravens, San Diego and Jets are a few examples of vertical offenses. At their best they have large physical lines, power running backs, and a big arm Quarterback. These teams typically produce solid running games but the statistics of their QB's are often lower than those of a horizontal game because of the degree of difficulty of attempts.
The passing game in these offenses ideally are designed as a secondary option after the run. They have bigger rangier receivers often drafted high because of pure physical ability. The passing game doesn't depend on accuracy as much as it depends on scoring, or at the very least the threat to score over the top. Because of the physical nature if a defense doesn't react by bringing a safety up, then the offense will continue to pound to force that. When looking for a Quarterback you look for one that has a huge arm ala Barkley or RG3. Accuracy and Timing isn't as important, rather raw power and the ability to counter a power running attack.
In a horizontal system it is all about space. Typically these offenses are going to require quickness all around. The goal is to spread out defense and create favorable match-ups in space. Green Bay, New Orleans, New England, Indianapolis are a few examples. These offenses are typically going to produce the more efficient QB's in the NFL, and be statistically superior to QB's vertical offenses. That's because the degree of difficulty in the attempts are lower. One reason is physicality isn't as important as technique and skill.
Accuracy, timing, and quickness is at a premium for a QB. Often times a GM will overlook arm strength and favor accuracy. Also intelligence is important, rather than physical gifts. In a horizontal offense the quarterbacks don't have to be prototypes rather just quick with their release and reads. Andrew Luck will be a great fit, where RG3 has greater bust potential, because the offense doesn't cater to his strength which is a big powerful arm.
Great Teams
The misconception today is that a QB makes a team. Which is true but systems are just as important. Put Aaron Rodgers on the Raiders and force him to depend on beating defenses over the top, and you have a different QB. What makes Rodgers so great is his talent is tailor made for the offense that Grenn Bay runs. Also when Pittsburgh is at it's best it's not when Rothlisberger is statistically dominant, rather when that running game is statistically dominant.
We get confused because Flacco and Sanchez don't pass the eye test but have results that compare to their statistically greater counterparts. Not to diminish the importance of a QB, but the offenses that Flacco, and Sanchez play in require them to pass to score. Which is different than an offenses that pass to win. The running game wins, and in reference to the Steelers have been the backbone to their championships. That's why Bradshaw baffles people who rank QB's based on championships, when Marino has none. Bradshaw, Sanchez, Flacco are examples of QB's asked to score, not to win.
How do the Chiefs fit?
My biggest criticism of the Chiefs is that they haven't identified who they are. They are neither a horizontal or vertical team. People want a QB, I want a system. At the top of the NFL, it isn't the best QB's that win. Rather a combination of system and personnel. Haley has to understand that, well before he identifies a QB. There isn't a quarterback in the world that can win a Superbowl without the aide of a system.
If the Chiefs want a horizontal system then they shouldn't draft RG3 or Barkley. Both have huge arms, but the offense requires a passer not a thrower. If they want a vertical attack then both would be great options and be a compliment to the skill set already in place. But that means getting larger linemen in place of Lilja and Wiegemann. That means what do you do with McCluster and Charles?
Many have tried to build around players and failed. As great as Adrian Peterson is, he is stuck in a west coast system that doesn't put him in position to be a championship caliber back. Rather a stat machine on an average offense. In New York for the Jets Peterson would be a perfect back. Marino was the greatest QB in history, but Shula never used his gift and give him a running game. Elway was in a similar situation until he got Terrell Davis to compliment that wonderful arm. System's matter as much if not more than a QB. Sure not having a QB is a problem but so is the inability to determine who you are.
