What I would love to see in future TES games is a skill selection system that lies between what was implemented in Oblivion and in Skyrim. I like the idea that you have to commit to certain skills (Morrowind-Oblivion) but I understand the problem of choosing these skills too early in the game (thus the freedom of the Skyrim system)
One of the frustrations I had with Skyrim is exemplified by the Speech-Mercantile skill. To me, selling the same generic iron dagger to the same merchant 100 times should not increase my Speech skill and especially not my overall level. With certain character builds I found it very annoying to have my overall level increased because I was simply selling off some of my loot. I often don't want my experience to be raised from skills I don't care about. This of course is due to the overall world-leveling that "follows" the player's level (without this feature there would be no problem). But it's there and has its advantages, and the Skyrim world-leveling was an improvement over the Oblivion one... which just made me want to stay below level 15... don't go to sleep after a certain level (when your combat related skills are at their peak).
What I want is a selection within the skills that allows for future changes but that also rewards the player for eventually sticking to a skillset. This could be implemented in a number of different ways, but here are a few ideas.
Basic Idea: The player chooses a limited number of skills from among the 18 skills (let's say 5 or 6 max). Selecting a skill would light up the first "perk" of its tree. This "basic perk" would be a major one which would give an important advantage towards the use of that specific skill. If the player wants to choose a different skill at some point in the game, he must de-select one them (which would free up a "slot") and choose a new skill. Doing so would lose the "basic perk" in the abandoned skill-tree. Also, in order to discourage a player from changing skills on a whim ( for example: selecting "lockpick" just before picking a lock and then de-selecting right after) the progress towards the next level in that skill would be lost each time it would be de-selected.
As for the skills that are NOT selected, it could work in different ways (not all exclusive):
A) Their level could simply stop increasing completely and all (or some) of their acquired perks could be disabled. This is one of the more "severe" ways I can imagine and it would be ok with me depending on how the game was implemented.
B ) Their Level could continue to increase with use but not contribute to the overall leveling of the character. This is less severe, but could potentially create some problems with certain types of "world-leveling" systems.
C) Their level continues to increase with use and it continues to contribute to the overall leveling, but the amount of increase is diminished by some significant percentage.
D) The most severe imaginable would simply be that the skill in question could not be used at all. Although this might work ok for certain skills (ex. magic: not being able to use the spells from that school), it might not be so great with other skills (ex. mercantile: not being able to sell your stuff at all) ( ex. bow: not being allowed to shoot with a bow at all).
My personal preference would be to let the skill level increase, but not contribute to the overall level. There should also be a boost to the increase of the skills that ARE chosen, and a temporary but significant loss of the acquired perks in the skills that are NOT selected. It could also just be the first "Basic perk" that is disabled; it would depend on the significance of the "Basic perk" and how it would influence the effectiveness and use of the skill (and the other perks on the skill-tree).
I would love to know what others think of such a system, and if there is already a topic along these lines, feel free to point it out.
Eventually I will post some offshoot topics which will be more concerned with specific Skills. I will start with Speech/Mercantile in relation to a "Selective Skill System". I think that the speech skill has a lot of potential especially if it was part of a selective skill system. I will post the link here when it is up for any Taloon fans who might be interested in that topic.