Swimming as Martial Arts Workout

This is on behalf of my husband, who has a number of questions. It is his post that he asked me to put here to anyone who might have good input on this. I know swimming is a great cardio workout and a good all around workout, but is it a good Martial Arts workout for developing the kinda of muscles and conditioning you need for martial arts? My wife is a swimmer and has gotten me into swimming now and I told her that I would give it a try for a few weeks and then see how to work it into a workout schedule. My wife wants to be a good swimmer, I don't want to be a good swimmer but I want to use swimming to improve my martial arts (if it can). My fear is that the swimming is very time consuming and that while it will give me good cardio and good a good general workout I will be missing in some areas and need to supplement with other areas. What I need specifically: 1) More endurance/stamina/cardio - a given for all athletes 2) More upper body explosive power. (I'm not strong in my upper body and need more work on chest and arm strength for power) 3) More leg work. I do Hapkido mixed in with Taekwondo, a lot of kicks and a lot strength needed in the hips/butt/thighs). This is just targets, I know I need it all in measures. My concern is that a) swimming won't give me the fast twitch explosive power need for strikes and that b) swimming favors more upper body, which I need, but I will need to use other exercises (pushups, weight and resistance, etc...) to develop the explosive power needed and I won't be getting the leg work I need. Top ranked swimmers have great bodies, but they get those bodies with dry land exercises in order to develop the bodies needed to be great swimmers. Home-run hitters work their timing, coordination, mechanics in the batting cage, but they get those muscles in the gym. I would love to say that swimming could be an all over workout for 5 hours a week, but I don't know if it will be the kind of workout I need, and I also don't know how I could tailor the swimming to get the kinda of workout I need, if possible.