It's a good point, Fidgit, but skill points represent training. INT checks aren't enough for everything, you still need to receive training in Knowledge, Profession, and Craft skills to be considered an expert. And, currently, there are only two base classes that can cheaply raise Knowledge skills other than the one corresponding to their class. That means that useful knowledge skills like History, Engineering, the Planes, and so on are effectively only available to two classes, because with the limited number of skill points everyone gets, no one is going to buy these cross-class.
This is why I compared it to Languages. If your campaign spends all its time in Sigil, you should have a few ranks in Knowledge: the Planes. It's campaign-specific, but under the current system you end up just giving them a circumstance bonus to the check. Same for if an Elf is trying to do a Knowledge check on Elven history.
I also was thinking about languages. In a way, they're too cheap, and I don't really like the Literacy requirement for Barbarians either (to me Barbarian is a fighting style, also called Berserker, not a culture). So, I wanted to create a Language skill. One rank gives you crude grammar (-2 to Bluff, Disguise, Diplomacy...) and not literate. Two gives literacy and conversational mastery. Three is full fluency, you can pass for a native (+2 to any Bluff, Disguise, Diplomacy, Gather Information, etc. skill check done in that language). Of the core classes only Bards get this as a class skill (making the cost 1/2/3 for them, 2/4/6 for others), although many classes also have a specific language that would be a class skill for them (Druidic, Draconic, etc.). Maybe expand each language to a 5-rank scale (crude, commoner, literate, educated, fluent). Maybe make it an INT-based skill so that you do "Language checks" to read something.
The catch is, instead of automatic languages, give each RACE a "race skill" list. This would include the languages on your race list, plus certain Crafts, Professions, and Knowledges. For example, give Dwarves the craft skills involving metal and stone, give Gnomes all the Knowledge skills, and so on. At each level, you get 1 skill point (4 at first level) that can only be spent on your Race Skills. Hopefully you'd spend the 1st-level ones on your home language.
Your classes might or might not have some of these as class skills, too, but this'd allow a little spending on these.