basically it all comes down to abilities. guards have 3 main potential abilities, guard skills, offense, and defense. for a player to be great, he has to have 2/3. generally that is true just to be good, but sometimes especially in d3 and low d1, you can get by on 1 if you are decent in other areas (especially if that one is offense). this guy is good in terms of guard skills but not strong defensively or offensively, so he leaves you understaffed in some key area. the general rule of thumb i give everyone i help with teams or mentor or coach with, is, you have to have a clear strength in 2/3 abilities on every single player (with the two exceptions being a lead scorer who is solid in something or a sf who has 1 clear strength and is solid in the other 3 - SFs have 4 abilities while everyone else has 3). if you think about that, thats 10 abilities per starting lineup, which would look something like 2 guard skills, 2 rebounding, 2 offense, 4 defense, which is generally enough to compete at the top tier of any division.