You seem to be confusing the measuring of tempo (speed) with the quantitative counting of music (for the purpose of determining rhythm, phrasing, total length of song, etc).
When counting music, there is no right or wrong... you can use whatever method is comfortable for you. Some people like slows and quicks, some beats and bars, etc. There are dozens of counting methods -- the one you use will depend partly on what you're accustomed to, and partly on what's appropriate for the situation.
On the other hand, when we're talking about tempo, we're simply describing the speed of the music. Counting really has nothing to do with it. So regardless of how one may choose to count his music, the tempo should be described in a way that is correct and accurate. To this end, beats are suporior to bars for reasons I described prevously.
Think about situations where you would see a description of tempo. The back of an album. A website. Sheet music. What is the purpose? To give an accurate representation of the speed. Perhaps to compare it to the speed of other songs for the sake of context. It's not there to help you count. It's there to give you a numerical representation of speed.
Numbers are ideal for describing tempo precicely because they are absolute. 2 is fater than 1. 8 is slower than 9. Period. It's immediately recognizable... there are no conditions or qualifiers. Everything is absolute. Nothing is relative or subjective.
When you use bars, you can honestly say that 20 is faster than 25. I know it sounds wrong, but it's true. When you use bars, you introduce the concept of time signature, which adds relativity. Now in order to know the true speed, you need to know not only the number of bars but also the time signature, and then you need to do some math to come to a final conclusion. 25 mpm is only faster than 20 if both are in the same time signature. If 20 is in 4/4 and 25 is in 3/4, then 20 is faster than 25. How many dancers do you know that would realize a Foxtrot at 20 mpm is faster than a Waltz at 25?
Have you ever looked at a metronome? A metronome is an instrument whose sole purpose is letting you hear the tempo. Every metronome ever produced has always used beats per minute as its unit of measure. If there was ever a metronome that used bars, it would have to also have an additional switch for time signature. Slide the little slider to 30 and flip the switch to 4/4, and the clicks would sound 2 per second (120 bpm). Now leave the slider on 30 but flip the switch to 3/4, and the clicks would suddenly slow way down. The tempo is still 30, but because the time signature changed to 3/4, the clicks are only sounding 3 every 2 seconds (90 bpm).
Of course, there's no such metronome. Because only dancers measure tempo in bars per minute, and dancers don't use metronomes. But the truth is, the only reason they don't switch to beats is not because it's better or worse, but simply because of convention. Much in the same way Americans to this day have not switched to the metric system. It's obviously superior, but when you've spent your life talking about inches, feet and yards, it's very difficult to retrain yourself to think any other way. You might even trick yourself into thinking inches and yards are better. But those with experience in both units of measure know better. The same goes for tempo. Any dancer/musician will tell you the same.
Your concerns about the theme to Pearl Harbour, Feathers and Three Steps and drivinga actions are not relevant to the discussion of how to measure tempo. No matter how the music makes you feel, tempo is an absolute, and should be measured absolutely.
Regards,
Jonathan Atkinson
www.ballroomdancers.com