Re: about training capacity
did you see a doctor about your knee ligaments? I got mine ruptured doing a wrong tai sabaki (with the weight of a stubborn uke on me), and when I went to the hospital in order to ask what it was (thought the knee was dislocated), he said I had two choices:
- either, for elder people or for those not doing intensive sports/ training/ martial arts...just let it recover naturally, with some physiotherapy for strengthening the supporting muscles. No surgery, but there would be the risk of arthrosis due to overstraining if I'd swim, continue aikido etc.
- or, for younger people and those doing intensive sports/ training/ martial arts => operate it, either immediately (that was too late for me because I waited 10 days before going to the hospital) or after > 3 months, in order to let the swell go down. I had the surgery, and everything was fine afterwards (htat's for three years, can't say what will be the long term outcome).
So if you want to continue aikido or any other martial art or intensive sport etc., maybe you should do something about your knee. From what I understood, doing nothing is dangerous at long term, and with 30 you are not old, you have decades to develop an arthrosis, and that's certainly not what you want. One of our elder sempai has arthrosis (worked as a truck driver, and that got on his knees), and he's off the mat ever now and then, it hurts, and there are lots of techniques he can't do properly anymore because of his knee. He's 67.
Coming to the gap between power and skill - I suppose that's maybe extreme because powerlifting and aikido are so very opposite. If you lift weights, you work on muscles, in aikido, you work on flexibility, reaction and spatial perception. You'll certainly often hear from your sensei "don't use force!"
But very strong people are often very rigid and have much more problems in receiving ukemi than small, thin or frail ones. Most of the lightweights in my dojo and elsewhere fall like cats or like leaves. The strong men fall like blocks of concrete. Same for locks - we bend, you break. We have a newbie who is a construction worker, and he started on advice of his doctor. The doctor said that aikido would do him good because it would help him to relax his shoulders. I suppose lifting 50 kg cement bags is not so different from powerlifting...
So maybe at long term you will become a brilliant aikidoka, but at the beginning I suppose the skills and strength you got from powerlifting are rather an impediment than an added value for aikido.
Wishing you all the best for your aikido and especially for your health,