The law of thermodynamics, i.e. calories in and calories out has never been proven.
Exercise facilitates weight-loss through hormone stabilization and detoxification, but eating a good diet of quality, natural whole-foods is the most important component. The calories burned are irrelevant as physical activity increases appetite.
2. Walking is an excellent exercise:
Walking is an activity, but not an exercise unless your health has deteriorated to the point that walking has become strenuous. Exercise requires intent and intensity, it has to be challenging. Proper exercise will need to include brief and periodic maximal physical exertion. Routines such as Tabata and HIIT have proven to be extremely favorable for insulin stabilization, whereas a steady aerobic pace like jogging actually has a negative effect.
3. The more the better:
Just because human beings have an incredible capacity for physical feats of strength, endurance or flexibility does not make it health promoting. I would argue that extreme lifting leads to joint problems in the long term; extreme endurance feats with prolonged periods of intensity, in the long term lead to heart damage, including valve prolapse and decrease in muscle mass; flexibility required for intense acrobatics and gymnastics leads to joint instability and deformities, which leaves the person in chronic pain and loss of functionality.
4. Routines incorporating agility, strength, balance, flexibility and endurance all at once:
Sure all of those attributes are signs of youthfulness and athleticism. However that does not mean you should be performing military presses while on a balance ball. Such activity might impress for a circus performance, but is not anything anybody would functionally ever encounter in a real life situation and will only lead to unnecessary injury. Regular calisthenics, yoga, free weight or kettlebell type of routines performed with proper form and function easily ensure all of the titled attributes. Many routines have spawned from rehab exercises, sports specific training or even to achieve a specific “look” on a movie set. That actually makes them goal oriented for a very narrow aim, rather then all-around health and vitality.
As with everything in life keep it natural and functional for optimal health, regularly performed balanced routines are most important.