"Its takes A LONG TIME to progress, possibly months or even say a year to reach the top tier of skill/ability"
I think then it would be almost impossible to max out any ability... Have any of your characters last a year without dying?

Expect from this, I like the idea very much.

Its just a suggestion. The whole point is to make the player MORE valuable than the gear. If you care more about your character than the gear then you will look after him better, maybe not make rush judgements and apply more thought to how you traverse the environment. There may be no reason then why you could not survive for months etc.

again, its a thought process rather than a finished system.

I'm not sure if this exact implementation is the way to go, but one thing is certain. Characters definitely need more value.

Players need a firm reason to never consider simply killing their character and collecting their items from the corpse.

I will never agree with something like that.
If you need to improve your character grinding or farming then you have to follow a different path and play other games such as jrpg or mmorpg.
Is not important how many time is needed to gain skills, the concept of skills are wrong (and will be everytime someone that will succed to cheat on gain). It seems to read about call of duty where you can choose from a pool of abilities that make character basically super hero.
We are talking about dayz, i don't wanna see "invisible and silent ghost players" going around the map stabbing map just because they have mastered some abilities, i don't wanna see iron man people keep running with never stop, etc etc.
Dayz is a simulation, you can not be a ghost, you cannot be an iron man...and it is stupid suppose that someone will make a lot of noise while sneaking because "he doesn't know how to make lower noise".

Except of equipments, the characters are the same yes but players not.
Every players approach the same problem with different ways ad tactics, each player has a different aim skill, different mouse skills, etc.

I don't like the idea that a character is more "stronger" than others just because he spent time online doing the same action 10000 times and now he will get good results just pressing a button; i like the idea that a player is more skilled than others because he spent time dealing with the environment.
For that reason i will hope that new features will be added such as wind for ranged shot and everything that could make the simulation experience much more hard, real and intensive.

Concerning the players interaction and the end game, a way could be give the possibility to set up gangs and capture/accupay buildings to build a proper base (maybe where is possible to have a farm or something like that). Base must be always conquerable in any time.

My personal idea.

I like the idea of giving your characters more meaning but the skill thing would be an open invite for hackers to bust a nut. Now Ive seen another report for beards, this is the way to give your character meaning. Grab a machete and carve yourself a sweet beard to show folk how long youve been alive... Ive considered the idea of skillbooks which would be easier to implement but again would ruin what DayZ is at its core... a survival sim