I feel that striking is natural to everyone, its something people do by nature. I mean little kids throw punches...
A bit of an aside, but I strongly disagree with what you are saying regarding striking being natural, and I'm basing it on 3 years of experience: throwing a proper, true boxing style punch is absolutely *not* natural at all. Throwing crappy, loopy, arm-only haymakers that have no power and will leave openings the size of a bullseye on your head to a good boxer is what is natural. I recommend you go spend some time in a boxing gym and then see how you feel about that statement. The more time you spend with striking (boxing/kicking) the more deep you will find it is, in part b/c it has additional dimensions such as range, footwork, etc. which grappling does not. My main point, though, is you should not mistake that striking is natural - nobody can walk into a pro boxing ring and go much further than 1 round with only natural training (watch toughman for proof of that), you have to learn very unintuitive techniques to really transfer your max power in a punch. That being said, I realize you are talking straight MMA and there aren't that many skilled boxers in MMA so the second half of your statement, that you can get away with just the basics is probably true until you do happen to run into a good boxer.
Anyway, to get back to your original question - you need to find where your natural talent lies, and maximize that and minimize your weaknesses in the remaining areas. You are not likely to become a champion by "not being bad at any area" - you have to be excellent in at least one thing so that you have a way to win offensively, and then reduce your ability to lose in the others. Crocop is a good example of that - everyone said you can't win in MMA by kicking but he's nearly kicked his way to the top by being great at one thing, something he obviously has natural talent for, and minimizing his weaknesses in the remaining areas. A lot of people say you should be perfectly 50/50, but the bottom line is people always have a knack for one area better than others...so you have to exploit that, while minimizing the weaknesses in the other areas (since you do have to be well-rounded to survive the times in your opponents strong area).
If you've been training for about a year and have the basics down of both striking and grappling, then I think you need to make a gameplan with your trainer that emphasizes your strengths and abilities (e.g. where can you win, and where do you have to avoid losing), and minimizes your weaknesses, which means spending more time in one area than others. Also, I would let your trainer/coach tell you where you are better at things, and not just your own assessment.
If you have not been training at least a year then you are probably better splitting it down the middle b/c you first have to have all the basics down to survive, then later build up your area of expertise.
Hope that helps!