I'm not MGoStaff but I've read a lot of these, and I feel like there's a lot of confusion with regards to how stars are handed out.  That said, I feel they've been pretty consistent, so here's a summary:
 

CYANS are OBJECTIVE, in as much as this is FBS-level football.  The primary caveat is if everyone is terrible, they don't want to cyan the entire roster (what would be the point), so they'll hunt for excuses to avoid doing so, making some cyan-worthy players appear better than they are.  Otherwise, a cyan'd player is a walking harbinger of Bad Things.  He could still probably dominate a beer league, but is going to earn only infamy in a nationally televised game.  (But these days cyans can also be handed out as jokes.  Point is, FFFF is not scientific.)

INDIVIDUAL STARS are RELATIVE.  OK folks, pay attention.  Star does not mean "elite", per se.  It means you look at the squad like you were a scout and say to yourself, "OK, whom do I have to worry about."  For example, Jaylin Lucas may not be that great of a player, I don't know, but he's by far the most dangerous player on Indiana's offense, so the star really means "pay attention to that guy".  He's a focal point.  A "star" on a mediocre team could project as a UDFA, if everyone else is playing at the FCS or high school level.  The same player wouldn't get a star at all on a ranked team, because. . .

MULTIPLE STARS [in a position group] are RELATIVE, but in a different way.  This is the "rule" that in my experience leads to the most grumbling.  Ostensibly the premise of a star is that a player stands out, but when everyone is good, no one stands out, so everyone within a position group might out-talent their opponent and yet no one gets a star, whereas the opponent gets one.  That does not necessarily mean the opponent's star player is better than everyone in the opposing group!  So the usual complaint goes, "Normy McNormface gets a star but Mich O'Homer doesn't?  OUTRAGE!!!1!"  Well, that's because although Mich might be a better player than Normy, he doesn't stand out because everyone on his team is equally better.  For multiple players in a position group to earn stars they need to be elite, the kind that routinely rack up +2s in UFR.  Kris Jenkins is like that, so he gets a star even though he plays next to Mason Graham.  He's just that good.

What this means is that it is harder for a player on a well-performing group to earn a star than a player on an underperforming one.  It also means a position group with multiple stars is legitimately formidable.

SHIELDS are OBJECTIVE. . . mostly?  Shield means you are grading out as one of the best few players in the country at your position.  Not merely "very good" or even "elite", but very likely getting drafted first or second in your position group.  Kris Jenkins (#16 per PFF, IIRC) is a very good player but Mason Graham (#2 per PFF) is one of the best DTs in all of college football, so Graham gets a shield and Jenkins doesn't.  In fact while I'm a big Sainristil fan, I wonder why he got a shield.  Darn good player and thank god he's a Wolverine?  Hellz yeah.  One of the best 2-3 slot corners in the country?  Ehhh. . . I'll never get tired of watching his endzone PBU against Ohio State, but just last week he beat straight-up by a non-elite receiver.  I don't think he's a Day One draft pick.

That's how I see it, anyway.  Maybe someone will chime in and go, "Bad dragonchild!  As an MGoUser, you are
!"

Despite all my rage I am still just sighin' in my cage. . .