Once again, this has little to do with possibilty so much as reliabilty.
A person might be able to kill a mountain lion by putting out its eye with their thumbs.
But if you had to plan how to kill one, would you plan on doing with a sniper rifle or with your thumbs?
Thats what we're doing when we train, we're making a plan.
Sorry if I seem rambling.
Ahh: but there, indeed, is the rub:
Self defense isn't something you PLAN for like a cage match; it is something that just happens like an animal attack.
If you are PLANNING to go out and kill a great white shark or mountain lion, sure: grab a sniper rifle or a harpoon.
But then to take THAT logic and then say, "Why bother training eye strikes? A sniper rifle or harpoon is proven to be MUCH more effective ..." doesn't make sense.
If you are planning to compete in a UFC match, I can see the benefit of coming up with a specific plan for dealing with a specific opponent. That makes
perfect sense.
But then again, to address the topic of "well rounded," if you are tailoring your responses based on what you see in the ring, you could very well be unprepared for some of the things that happen OUTside the ring.
And don't take this wrong: I'm not saying training MMA is not effective for self defense.
But one thing that has been proved over and over again is, "training is highly specific."
Experience has shown me (from newbies showing up at the dojang) that completely untrained people are very often unpredictable* it stands to reason, therefore, that having a wider range of possible responses is desirable if training for self defense is your primary goal.
And something that is reliable IN the ring pulling guard, muay thai clinch, rear naked choke could put you in a position to be seriously HURT outside the ring where the possibility of additional attackers is real and even in some places likely.
Sorry about the tangent; it always seems to happen in these discussions, eh?