There's a certain base value for each stat which doesn't get taken into account for purposes of derived stats. The easiest one to spot this with is the health increase from Stamina (Or the Mana increase from Intelligence).
These are generally small little things, but could account for a fair amount of variance when trying to figured out how some other stats are derived. For a Blood Elf Paladin for example, the following amounts of Strength, Stamina and Intelligence don't seem to get counted for Attack Power, Health and Mana respectively (And thus presumably for other things as well).
Strength: 10
Stamina: 18
Intelligence: 18.66
The same is probably true for all races/classes, and is probably to account for racial stats or somesuch.
I'd suggest that instead when trying to derive stat formulas you assume that your stats naked are 'zero' and than attempt to figure out the rate of increase each point gives from there. In your above table, that'd basically mean reducing all Intelligence values by 131 and all Crit% due to int values by 3.30%. That way you also make sure your values don't get muddied by any base crit values you'd have even with no intelligence.
There's no need for more intelligence being needed for more spellcrit in the system either; the ratings scale with level, the amount of intelligence you need for spellcrit does as well.
As I'm bored, here's the table as revised according to my suggestion (I've removed the crit rating and normal crit chance as they don't matter):
Intellect Crit% due to Int Int:Crit%
0 0% 0.00
6 0.07% 85.71
7 0.08% 87.50
8 0.09% 88.89
10 0.12% 83.33
13 0.15% 86.67
15 0.18% 83.33
16 0.20% 80.00
17 0.21% 80.95
19 0.23% 82.61
21 0.26% 80.76
22 0.27% 81.48
25 0.31% 80.65
27 0.33% 81.82
29 0.35% 82.85
32 0.39% 82.05
37 0.45% 82.22
44 0.54% 81.48
46 0.56% 82.14
84 1.03% 81.55
123 1.50% 82.00
152 1.85% 82.16
170 2.08% 81.73
255 3.12% 81.73
Note particularly that apart from the first 15 Intellect, the variance in the last 240 Intellect could easily be attributed to rounding and the Int:SpellCrit% ratio is quite close for all those values.