This is an interesting idea.
Obvious benefits:
Selection derived from a race including top Kenyans and others among the world's best.
Obvious drawbacks:
Many, many Kenyans with a legitimate claim to being in the trials race will simply be unable to attend.
Announcing the trials race only three months beforehand?? Only in Kenya.
Thing nobody is getting:
Athletics Kenya is a notoriously fickle, unpredictable, borderline corrupt agency. (I'm being kind by adding "borderline.") It's not as if this "trials race" is going to be "first three across the line are in."
It's going to be "first two across the line might be in, unless they dared to run in a US road race for $50,000 (instead of the AAA Battery Kenyan XC Series for $100), and third place might be in, but probably some old favourite from 2004 who AK owes a favour will take the spot."
Try explaining THAT to a live audience.