I would just generalize it into being that it's missing details.Details enhance a picture a lot and makes it more interesting to look at.But overdoing it isn't good either...
IMO, it just isn't worked enough. It's not really that there are no details, it's just that it looks like a large part of the piece looks like it was sloppily done in a few minutes.
drawn in 24 min
lol.
I agree with both of them.
PS. Star of David has six points...