Game Flow, mechanics vs realism

OK, AD&D 1st edition suffers from some basic drawbacks in the mechanics.

The Mechanics are what makes the game, I have my players make the least of amount of rolls possible. They mostly will roll only for things that directly affect them

Here are some of the way I make the mechanics work for Game Flow...

• Encumbrance
• This is the most misused and least understood rule as well as ignored rule.
• Simply, if you as a person could not carry it, your character cannot, If you think your character can, then you need to prove it. 
• Reasonable Encumbrance is used as not to waste time during game... 
• Weapon Speed
• Throw this one out, this works in 2nd edition where you use a D10 for initiative, but never worked in 1st Edition where you use a D6 and all things happen at the same time. 
• If your strength is 18/75, you can wield a Two Handed Sword as fast as the thief with a 14 Strength and a short sword
• Casting Time
• For the most part, any casting time longer than 3 segments happen at the end of the round and any longer than 7 Segments happen the beginning of the next round if they win initiative. 
• Ability Checks
• This rule is not clear in 1st Edition and many people use a D20 and you roll under the ability
• I Prefer using D6 and rolling under the ability. 
• When required (basic ability checks are automatically successful)
• 4D6, Roll under the ability
• Example
• Attempting to run across a log over a ravine while chasing someone would require a dexterity check of  4D6 (possible 5D6 if wearing plate mail) with a Dexterity of 15, the roll is made (13 is the total) and the action continues.... A failed roll would not mean that the Player character falls (Unless he rolls all 6's) but possible was not quick enough over the log. By the same logic, all 1's would enable the PC to make up significant ground 
• Critical Hits
• For Critical hits, I try to add a bit of realism with a Lucky Shot
• On a Roll of 20, I have them Reroll 
• 1-5, Normal Damage
• 6-10, Max Damage
• 11-15, Double Damage
• 15-19, Triple Damage
• 20, Instant Kill
• Same apply for Players, but 20 equals Zero HPs
• On a Roll of 1
• 1, Weopon Broke, dropped, Lost 
• Bow String Broke
• Sword, save vs crushing blow, automatically dropped out of reach for the next 2 rounds
• Dagger, dropped or missing if thrown
• 2-10 Dropped, one round
• 11-19, Lose attack for the round
• 20, Normal

A long time ago when I first began Dungeon Mastering, I read an article in Dragon Magazine that changed how I approached my passion... 

This is from Dragon Magazine #52

It is my belief that the game should be absolutely portable first. with a minimal of "House Rules" if it takes more than 2 minutes to do any rules clarification, then I am not interested in playing

From The Dungeon Master's Guide, 1st Edition

“It is the spirit of the game, not the letter of the rules, which is important.Never hold to the letter written, nor allow some barracks room lawyer to force quotations from the rule book upon you, if it goes against the obvious intent of the game.... You are creator and final arbiter. 
By ordering things as they should be, the game as a whole first, your campaign next, and your participants thereafter, you will be playing ADVANCED DUNGEONS & DRAGONS as it was meant to be.”