I'm finding it more and more common online nowdays that people are afraid to choose any race other than the one that the game claims is "best suited" to the class they want. Many hunter players are scared to stray from Beasts, while many rangers choose a CAST without a second thought. This sort of superficial mentality is caused by the in-game claim that each race is made to perform a certain role; an assumption that could not be more false.
I am of the opinion that, in most cases, any race will do just as well as another in any class.
I play a CAST hunter, and as far as I can tell, I'm just as good as any Beast hunter out there. Some think that CAST should mainly stay with ranger because they have high ATA, forgetting that hit rate is important in close combat as well. A beast will outdamage a CAST if they connect, but the fact that a CAST will connect more often balances it out in the long run. Plus, even though a CAST can't match a Beast's HP, they can absorb damage like no other with their high DEF, and their EVA isn't that much less. The only real problem is the fact that CASTs won't be able to use the better weapons as quickly, and weapon quality only really begins to have a greater impact in later levels when people are using rare equipment. By the time you're high-leveled enough to find that kind of weaponry, that won't be much of a problem anyway.
Likewise, a Beast can make a fully capable ranger. Now, I know that I may have sparked something along the lines of "Omg you noob, Beasts can't hit for ****" in the minds of some by saying that, but hear me out. Beasts will be hurting in the mid-early levels due to their low ATA, but because of the fact that lower leveled creatures can't evade much, your first few levels won't be all that horrible. By the time accuracy becomes an issue, you can just spend a little time grinding to raise your class level and getting your bullets up to spec (and maybe even add an ATA unit to your armor.) This sort of problem will level out later as you gain more ATA boostage from leveling your class and bullets anyway. All that being said, a Beast's high ATP will allow them to dish out some serious damage as a ranger, especially with higher leveled bullets (which you won't have to worry about, as the drop in END from CAST isn't all that bad.)
The only race that will really have a problem with "unrecommended" jobs would be a Newman as a hunter or ranger, something that will be more feasible when advanced classes are released.
I think that if you weigh the strengths and weaknesses of each race, they all more or less balance out with each other. So remember, don't worry about gimping your character when you want a slightly different mix or race and class type. Just take a breath, and start playing, and you'll be :):):):):):) monsters with the best of 'em.