Mustrum_Ridcully
Legend
I like the Iron Heroes skill system for the simple reason that it is a lot easier to build up a skill that is not "core" to your character class, and you can still be good at what your class is supposed to be good at.
In D&D 3.x, a Fighter can surely try to take ranks in Hide and Move Silently. But don't expect him to be really good at it, and do also not expect that he will be good at any other skill Fighters are usually associated with.
The skill points cost for cross class skills are probably the most notable problem with D&D 3. It's okay that I can't get as good as it as a character that has the skill as a class skill, but deciding to do something outside of your main character role becomes so expensive that you can't fulfill your main role, either.
Iron Heroes solves this problem by reducing the cost for cross class skills and also making it easier to be good at your core skills.
But there is a second problem with the D&D skill system: If you never bother to spend points on a skill, at some point you will have little chance of using it effectively at all. All skills that require opposed checks are out very quick.
There are some skills in which this might make sense (maybe people really never get better at Diplomacy or Spellcraft), but for others, it makes little sense (Spot and Listen for example - these are the kinds of checks that every adventurer constantly makes)
The Saga system assumes that every skill advances as the characters general experience grows. I like that approach.
D&D has a few other mechanics that work the same way: BAB, HD, Saving Throws. They always advance. There is a simple reason why they always advance: Everyone needs them for the "core" of the game system (which is combat.). You can't have a character whose Hit points don't improve, or whose saves don't get better, because he will be overwhelmed in a typical combat situation. That's why these abilities are not skills (unlike as in most class- and or level less systems), they just improve with your level. Sure, they improve at varying rates, but they improve constantly.
The D&D default assumption is combat. Skills are supplementary. They are nice to have, and they give you opportunities outside of combat. But it's also obvious that you don't really need them. I don't know any published adventures that couldn't be run without social skills, and most can also go by without trap-finding (though in many, this will be costly.) But are there any adventures that can be done through skills alone? You might thing Diplomacy is enough, but try using Diplomacy against a mindless undead or construct guarding the adventure's "McGuffin", as an example.
Combat is always a possible fall-back solution. It's rare that this woulnd't work in some way (and if it doesn't work, players might find out to late and their characters are all dead by then.)
Combat can only be this fall-back solution because everyone is getting better at it. Skills aren't that reliable, because in any given group, people might lack the required skills.
The Saga system for skills addresses this problem. It assumes that everyone needs some basic competency in skills. And since the skills have been restructured to have less skills, it is also easier to ensure that the group as a whole won't lack necessary skills. That makes it a lot easier to build adventures that might work out without ever needing to resort to combat, because everyone has some basic competence in the area of "non-combat". (Though I doubt that this will mean that this will always happen a lot in a system for a universe called Star WARS.
But it's nice to have this option.)
Iron Heroes also improved the skill system a bit further than just making skills easier to get. It also gave them (more then before) uses within combat. Which meant that people relying more on skills could also use them in combat, so they don't have to focus on combat alone - their skills can compensate for lack of pure combat abilities.
Okay, so this sums up the advantages of using a system like the SAGA skill system, preferably combined with aspects of the IH system.
It is still true that there are some shortcomings:
You might ask: "What if I want to have a character to be really bad at something and never getting better, because that trait belongs to his personality and I don't want to lose that.*"
My answer might be: "You will have to ignore your "general competency bonus" and avoid using the skill. But on the bright side, if you ever want to play a Fighter that can also sneak around a bit with a real chance of remaining some competence in Climb/Jump/Swim, you can at least do that now."
I think this fits the "options, not restrictions" paradigma very well. If you want restrictions, impose them yourself. But if you want options, the game system is there for you.
But, as always, your mileage may vary...
*)
In D&D 3.x, a Fighter can surely try to take ranks in Hide and Move Silently. But don't expect him to be really good at it, and do also not expect that he will be good at any other skill Fighters are usually associated with.
The skill points cost for cross class skills are probably the most notable problem with D&D 3. It's okay that I can't get as good as it as a character that has the skill as a class skill, but deciding to do something outside of your main character role becomes so expensive that you can't fulfill your main role, either.
Iron Heroes solves this problem by reducing the cost for cross class skills and also making it easier to be good at your core skills.
But there is a second problem with the D&D skill system: If you never bother to spend points on a skill, at some point you will have little chance of using it effectively at all. All skills that require opposed checks are out very quick.
There are some skills in which this might make sense (maybe people really never get better at Diplomacy or Spellcraft), but for others, it makes little sense (Spot and Listen for example - these are the kinds of checks that every adventurer constantly makes)
The Saga system assumes that every skill advances as the characters general experience grows. I like that approach.
D&D has a few other mechanics that work the same way: BAB, HD, Saving Throws. They always advance. There is a simple reason why they always advance: Everyone needs them for the "core" of the game system (which is combat.). You can't have a character whose Hit points don't improve, or whose saves don't get better, because he will be overwhelmed in a typical combat situation. That's why these abilities are not skills (unlike as in most class- and or level less systems), they just improve with your level. Sure, they improve at varying rates, but they improve constantly.
The D&D default assumption is combat. Skills are supplementary. They are nice to have, and they give you opportunities outside of combat. But it's also obvious that you don't really need them. I don't know any published adventures that couldn't be run without social skills, and most can also go by without trap-finding (though in many, this will be costly.) But are there any adventures that can be done through skills alone? You might thing Diplomacy is enough, but try using Diplomacy against a mindless undead or construct guarding the adventure's "McGuffin", as an example.
Combat is always a possible fall-back solution. It's rare that this woulnd't work in some way (and if it doesn't work, players might find out to late and their characters are all dead by then.)
Combat can only be this fall-back solution because everyone is getting better at it. Skills aren't that reliable, because in any given group, people might lack the required skills.
The Saga system for skills addresses this problem. It assumes that everyone needs some basic competency in skills. And since the skills have been restructured to have less skills, it is also easier to ensure that the group as a whole won't lack necessary skills. That makes it a lot easier to build adventures that might work out without ever needing to resort to combat, because everyone has some basic competence in the area of "non-combat". (Though I doubt that this will mean that this will always happen a lot in a system for a universe called Star WARS.

Iron Heroes also improved the skill system a bit further than just making skills easier to get. It also gave them (more then before) uses within combat. Which meant that people relying more on skills could also use them in combat, so they don't have to focus on combat alone - their skills can compensate for lack of pure combat abilities.
Okay, so this sums up the advantages of using a system like the SAGA skill system, preferably combined with aspects of the IH system.
It is still true that there are some shortcomings:
You might ask: "What if I want to have a character to be really bad at something and never getting better, because that trait belongs to his personality and I don't want to lose that.*"
My answer might be: "You will have to ignore your "general competency bonus" and avoid using the skill. But on the bright side, if you ever want to play a Fighter that can also sneak around a bit with a real chance of remaining some competence in Climb/Jump/Swim, you can at least do that now."
I think this fits the "options, not restrictions" paradigma very well. If you want restrictions, impose them yourself. But if you want options, the game system is there for you.
But, as always, your mileage may vary...
*)
I could add: "But I don't mind that my wizard who rarely tried to make a touch or ranged touch attack in his 12 levels getting better in combat and can take out a 1st level Orc Barbarian without spells or using my wit..." for some irony. But that would assume that you (or the imagined speaker of the sentence) actually don't see that as a problem and/or are absolutely resistant to changes to the system, which I doubt.