Hi Joni!
There are many methods of weight lifting out there. Most of these methods help to provide individuals with workout variety and also help to stimulate muscles in different ways. Since each individual has their own set of genetics and is motivated by different methods, what they look for in a workout and the results they acheive will vary too. The key thing that you want to strive for is finding a method(s) that suits your specific needs and motivates you to obtain the results you are looking for. If you can get and maintain those results by lifting in one specific manner, there is no need to feel that you have to totally change everything around and lift differently. However, if you are feeling like your program is plateauing or simply not motivating you anymore, then it would benefit you to try other methods to stimulate progress.
Regardless of what method you choose, these rules should always be followed: always use good form and technique, exercise safely and in a controlled manner, incorporate full range of motion throughout the various exercises and rep variety, and listen to your body's needs by modifying an exercise that doesn't feel natural to your body or granting it a rest day when it calls for one.
Based on your post, I was getting the impression that you feel that you have to do endurance workouts even though you don't want to. While it is true that you should experience both(training for muscular strength and endurance)to maintain a better balance, there is nothing wrong with favoring one method and doing much more of it. You can just stick the other method in your routine once a week or every other week to expose your muscles to the cross training effect.
My goals are a lot like yours when it comes to lifting weights. I personally like to get into one muscle group at a time and work it to the fullest as opposed to jumping all around and/or combining different exercises for different muscle groups and then returning back to touch on these muscles again later in the workout. Although there is nothing wrong with these workouts(and they even provide wonderful results for many), I have found that for me and my genetics, that these workouts provide more of a conditioning workout. I, therefore, choose to use these workouts for my maintenance workouts since, for me, they touch upon all my major muscle groups and keep them stimulated but do not present them with an overly huge challenge.
A suggestion: As far as your not being completely satisfied with the endurance selection available, you can always create your own endurance routine. Since you seem to enjoy keeping your focus on one body part at a time, simply write down 4 or 5 exercises for each body part that you like. Then do 3 sets of each exercise with a slightly lighter weight than what your used to and with only about a 10 to 15 second rest period between sets. You can just do the one body part in this manner or you can do 2 or 3. Since you will have so many exercises per body part, I wouldn't advise doing more than 3 body parts(per workout) since you would probably start to lose your focus. After your lighter weight endurance routine, add abs and a stretch at the end and your finished. The next day do the same thing with another body part(or if you happen to be doing a few body parts per workout, put two days between and then select another few body parts).
Hope this helps and sorry to be so winded.
