Mad Skillz: An Embryonic Proficiency System for "D&D" and "Pathfinder"

On the rare occasion when I've had an opportunity to play an RPG over the past few years, it's invariably been either D&D 3/3.5 or Pathfinder.  I've noticed that one of the main things that seems to confound newer players about these two systems are the rules governing Skills.

Although many OSR bloggers like James Maliszewski raise some solid points about the downside of any Skill system, I still like the idea in theory because it gives players an opportunity to flesh out their Characters a bit.  On the other hand, I also have a raging grudge-on for every Skill system I've encountered because:

1. Characters are given a generic dollop of Skill points whenever you reach a new level based on class.
2. Skill development often has little or nothing to do with "practice" or in-game usage.  
3. For new players the Skill block on the front page of the Character Sheet takes up too much real estate and looks like Neil Degrasse Tyson's daily "Things To Do" list.  

So I'm gonna implement the following system and what happens.  As a disclaimer, it's probably an amalgam of ideas I've gleaned from OSR blog posts and Google+ RPG discussion threads with my own connective tissue added for good measure.  If you helped inspire this idea, you know who you are. And thanks, BTW. 

THE BASICS

1. First off, multiply a Character's six attributes by five to generate a percentage.  Taking Jacinda the Irresistible from my previous example, her base Skill percentages would look like this: STR 13 (65%) DEX 16 (80%) CON 10 (50%) INT 9 (45%) WIS 10 (50%) CHA 13 (65%)
2. Use 3/3.5 rules to determine what "Key Ability" to use when a Character attempts to do something.  For example, if a player tries to Intimidate an NPC, this would fall under the dominion of Charisma.
3. Have them roll percentage die to see if they succeed.  As the DM you can declare that certain things can't be attempted untrained (like "Disable Device" for example).  Alternately you can also assign bonuses or penalties to the attempt.  If the dude that Jacinda is trying to Intimidate is a real milquetoast, then give her a 10% bonus!  Is he the evil Prince's right-hand man and knows that he'll be reduced to atoms if he blabs?  Nail her with a -20 penalty! 
4. Regardless of whether or not the attempt worked, instruct the player to write the name of the Skill, their Base Percentage and a single "tic" on their Character Sheet.  Every time they use that Skill in-game, get them to add a "tic".  At the end of the session, have them roll percentage dice.  If they roll under the number of tics, they get to reset their current tally to "0" and then increase their base percentage by one!  If they failed to roll under the number of tics, then this count carries over to the next session and can be increased.  
5. Players can also "Practice" their Skills.  If you deem that the PC has a free moment to "Practice" (such as breaking camp for the night night or in the comfort of their room at the Inn), they get to add two free "tics" to their Skill tally.  If they're taught by a PC or NPC with a superior Skill, they can increase it by five "tics".  

Looks okay in theory, but I need refine the following points...

THE CHALLENGES

• How can this system be used to build Thieves and Rogues?  Since that class is practically built around Skills, they should have immediate access to specialized skills and progress at double the normal "Practice" rate.  
• Related to this, character should probably get a healthy allotment of "tics" or Percentage point increases whenever they gain a level, representing a concentrated period of "Practice".  But how much?
• Naturally, DM's will need to be wary of potential abuse.  This can be as simple as telling players specifically when they have an opportunity to "Practice".  
• If a player wants to start with, say, a Level Five character, how can we best simulate what should have been an organic in-game Skill progression?  

It isn't perfect but it does attempt to address my main gripes with every system that's proceeded it.  

Questions, comments, suggestions and general belly-aching are all welcome below...