I have seen something like this before about 10 years ago. The biggest problem is look at how much equipment is required. You going to need a special unit just to administer the test. Although the APFT has its limitations, but the biggest advantage was that it does not require any special equipment and can be administered almost anywhere by anybody who can read the manual. It is a long way to 2020 and I predict it will not replace the APFT. I was a tanker in the Army, which is a job that requires raw strength to complete many of the common tasks of the MOS. In my experience, if the soldier could pass the APFT, then they could accomplish all of those tasks.
When I first came into the Army we had a 5 event fitness test which included: the Overhead Ladder; Inverted Crawl (kind of a crab walk forwards and backwards); the "Run Dodge and Jump "(a mini obstacle course in which you ran around obstacles and jumped over a trench; Situps; & Two mile run (in fatigues and boots). It was a really good test from the standpoint of measuring functional strength, but it was time intensive to administer, and it was really hard to train for. The overhead ladder was a combination of strength - with technique, and the only way to be good at it was to practice it, That meant ladders everywhere- shower rooms, hallways, outside. And as a friend reminded me- most of them were rusty and your hands were like hamburger at the end of doing a set (and as a stumpy guy- no matter how much I practiced, I was never going to max the perverted crawl no matter what I did!)
When they went to the current APFT- (which I think was in 1980 or 1981)- much of the rationale was exactly what Davejean90 lists above- availability of time and equipment to administer. We'll see if this new test really gets implemented- every month for the last 30 years the Army Times has been discussing a new PT test- and the current 3 event test is still here. I think that frequently they confuse the test with how they should be conducting strength and fitness training. The APFT is probably just fine as a snap shot of personal fitness- but it is not what PT should be about, which should be about building strength, endurance and cardio for the tasks required for your MOS.
The minimum standard has not been decided yet, that willl be the demise this test. If it is too low, the test becomes meaningless. If it is too high, not going or can’t afford to separate soldiers that fail.