I tried searching the forum, and while there are a couple of threads on the marksman skill, none seem to be about this question - which is how the marksman skill should affect ACCURACY. (As opposed to damage, perks, armor penetration etc)
This suggestion primarily covers how the marksman skill affects accuracy. Other issues, such as damage/armor penetration, are (as of now) not covered. The same goes for skill perks.
The intent is to come up with a suggestion that will make the marksman skill more realistic and rewarding wrt accuracy.
In Oblivion, even novice marksmen are able to hit targets pretty reliably, as the dispersion from the aiming point is negligble (by dispersion I mean archer-induced dispersion, not gravity-induced drop) Improving your marksman skill does not dramatically improve your accuracy, as it would in real life. Instead, the RL players(as opposed to the character) ability to judge superelevation is the key factor to hitting targets.
This suggestion involves creating a default dispersion whenever using ranged weapons, and allowing the marksman skill to modify this dispersion. The skill will do this in two ways. More on this later.
Default dispersion.
By "dispersion", I mean the random pattern arrows will make because of (small or big) errors on the archers part. This could be shaking hands, unproper string release, etc. This dispersion will be modeled by drawing an invisible circle around the aiming point. When you release the string, the arrow will hit a random point within the "dispersion circle". (The randomness might sound funny, but this is generally how accuracy works. There is ALWAYS dispersion, the key is to make it as little as possible) Better bows might have smaller dispersion circles, but for now we'll assume the only influencing factor is the characters marksman skill.
In order to make speed a factor, we'll use two dispersion circles. One "snap shot" circle, and one "aimed" circle. The first one is the largest, and is applied when the bow is simply drawn and immideately released. The aimed circle is smaller (ie, more accurate) and is used when the character takes some time to aim after the bow is fully drawn.
How the skill will affect it
The marksman skill will affect these circles in 2 ways; accuracy and speed.
1) Accuracy. Since the arrow will strike completely randomly within the dispersion circle, obviously having a smaller circle is good. The most important part of the new skill will be to reduce the size of the dispersion circle as the skill increases. As a novice, the circle will be very large, meaning you will have a very hard time hitting a target at all until you get some more practice. As you approach master level, the aimed dispersion circle will be no bigger than the circle in the cursor as we know it from Oblivion, making for very accurate shots.
2) Speed. Your skill level will affect how long it will take for your "snap shot"-circle to reduce itself to the "aimed"-circle. This is obviously a continuing reduction, but where a novice might take up to 3 second for the snap shot circle to reduce itself down to the aimed circle, the master marksman might only need 0,5 seconds to achieve "aimed" circle.
In this way, a skilled marksman will be considerably more accurate than a novice one, and will require considerably less aiming time to achieve maximum accuracy.
To illustrate, I've added two pictures. The "snap shot" circle is marked in red, while the "aimed" circle is marked with blue. (Obviously, these will be invisible in-game, and are marked for illustration purposes only)
http://img255.imageshack.us/i/marksmannovice.jpg/
Uploaded with http://imageshack.us
Novice marksman, note the large blue circle - all aimed shots will hit at completely random locations within this circle
http://img63.imageshack.us/i/marksmanexpert.jpg/
Uploaded with http://imageshack.us
Expert marksman. Much more accurate aimed shots, as the smaller blue circle illustrates. Also, not shown, the time required to go from "red" to "blue" circle will be much shorter than the novice marksman. Thus, the expert marksman is able to take faster, more accurate shots than the novice. (It will get smaller still as the player advances to master)
In the pictures, I haven't changed the sizes of the red circles. I'm not sure if there is a need for this - the expert marksman will reduce the red circle quite fast, so the dispersion is only as big as the red circle suggests for a quarter of a second anyway. The novice marksman may need a full second before the red circle even begin to reduce. So while the pictures may give the impression that both archers are equally accurate when it comes to snap shots, the reality will be quite different.
What do you think?