- It feels weird classifying people in boxes of desired contact frequency. How do you decide that? Does the author think "I honestly don't care enough about this person to contact them more than once a year" ? Then why are these people still "friends"?
- Lack of flexibility. Organic relationships will have different contact frequencies over time. For example, I might have inconsistent contacts with a friend that I've known for a long time because of reasons, but if they're having a rough time I will probably be more attentive and want to contact them more frequently.
- Relationships are two-way, so you'd expect that the other part initiates contact a significant amount of the times. Given the myriad of ways that contact can happen, updating the database for hundreds of people can be a real hassle. The fact that this is not mentioned at all indicates that a lot of these might be one-way relationships, not actual friendships.
- I find it really really hard to write non-artificial messages when contacting on a schedule. Maybe the first one can be believable, but the second or third time you contact someone without any obvious trigger, it starts to feel weird. I think most people would catch wind that the other person is not contacting organically but on some kind of schedule, and I guess it could make them feel really weird about it: "This person doesn't really think of me, doesn't see any of my social media/blog/whatever updates... why are they contacting me?"
I understand what other people are saying in the comments about forgetting to contact people or being too busy, and needing reminders. But I don't think that's the same problem the author is solving.