I think a tiered minimum wave system would be a huge mistake

Personally, I think the tier system is a mistake.  Let's take an 18-24 year tier as a for instance; it's easy for me to figure out). 

18-24s have double the unemployment in most modern economies.  Say US overall unemployment is 6.5%.  18-24 unemployment would then be about 13%.  A tiered wage might drop that to 8% at best (guessing) -- 5% more youth employed -- while 87% are being paid much less ($10 an hour instead of $15). 

100% of over 24 year olds will spend the rest of their lives looking over their shoulders, worrying that the underage are going to keep them out of a job (which may set up the "sneaky", when nobody's looking, race-to-the-bottom).

Ask the unders; and ask the overs: I suspect they wont think anyone would be doing them any favors. 

Nature's "light machine" -- hide the exciting inside the dull

Nature's formula for the spectacular but tasteful: hide an exciting property inside a dull property -- examples:

African butterfly (on display, New York Museum of Natural history -- last I looked, 1992): a bright red splotch in the middle of a highly refined black design.  Of course if you think the color black is spectacular color, the effect of the latter will be "gaudy" -- same principle.

Between the Museum of Natural History and the Metropolitan Museum of Art: multiple form sculptures expanded in most symmetrical ways to absorb maximum light and air -- constructed of gnarly, asymmetrical components.

Back in the East Village in the '60s I observed acid heads sitting around a "light machine" -- a contraption of blinking lights and revolving mirrors behind a translucent screen; projecting essentially an endless series of crayon streaks -- totally engrossed by the display for hours.  I wondered how you could program a changing display that would entertain somebody "straight."  The African butterfly display answered my question.

PS. Nature is not copyrightable.  :-)

"Obama-doesn't-care" -- versus -- the re-unionization path to economic and political recovery

Obama's “My Brother’s Keeper” initiative targets $350 million at poverty = 1/3 of one billion dollars in our 20,000 billion dollar economy ...
... or $50 million less than NY Mayor (stop-and-frisk) Bloomberg spent opening an unnecessary new Bronx courthouse in 2004.  The “old” 1939 court may be viewed above; a "new/old" $120 million court was opened (behind the camera) in 1976 to catch the crime wave of that era, which had receded 75% by 2004.  

Obama's $600 million dollars for a job skills program = 2/3 of one billion dollars out of our 16,000 billion dollar economy ...
... or $30 million less than Mad Mayor Bloomberg spent opening an (I presume) equally unnecessary courthouse in Brooklyn in 2004 ...

... both programs together = 1/16,000 of our economy = "Obama-doesn't-care."

E.I.T.C. (Earned Income Tax Credit) = adds up to $55 billion out of a 16,000 billion dollar economy.

$15 an hour minimum wage = multiplies * up to $560 billion out of a 16,000 billion dollar economy = 3.5% overall price increase.

$15 is about the 45 percentile wage.  Not to worry; 45% of our workforce is not going to be laid off over a 3.5% increase in prices. PS. This is not a zero-sum game; a large minimum wage should actually raise employment (in our demand starved economy).

[* 45% of workforce gets average $8,000 raise -- plus, the bottom 5% who are on minimum wage get a full $16,000 -- which amounts to 50% of 140 million getting an average $8.000 --  $8,000 X 70 million = $560 billion.]
 
 http://ontodayspage.blogspot.com/2014/01/raising-minimum-wage-for-45-of.html
http://ontodayspage.blogspot.com/2014/05/the-american-amoeba-economy-literal.html
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MY COMMENT TO: "Who will Save Us from Inequality" by Carola Binder at:
http://carolabinder.blogspot.com/2014/03/who-will-save-us-from-inequality.html

There is only one mechanically plausible way to rebalance the US labor market (and, because it means massive re-unionization, also reform the US political forum): a post-WWII, industrialist invented (that's right; not Marxist) setup called centralized bargaining -- legally mandated.

Under centralized bargaining (A.K.A., sector wide labor agreements) all employees working at similar occupations (e.g., retail clerk) in the same geographic locale (where applicable -- airlines would presumably take in the whole country) negotiate one common contract with all employers.

Wal-Mart recently closed 88 big-boxes in Germany where it could not undercut based on lower pay and benefits.

Where to start: supermarket and airline employees would kill for centralized bargaining. A few years ago Northwest Airlines squeezed a billion dollars of givebacks out of flight crews -- to be followed a year later by a billion dollars of bonuses for 1,000 executives.

Where it stops: not with you -- your are a female human. You are able to judge the saleability of a new direction strictly on merits of argument -- and not be totally mesmerized by the big world outside that always looks too big, much too big, to seriously change. You are an individual gatherer, instinctively.

Human males -- with their (our) pack hunter outlook -- always and immediately check with the world outside and almost always assume nothing can be done (maybe this is so only if we have no immediate personal stake -- which academics don't have in reforming the labor market). Have see this issue after issue over and over for decades.
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Realistic way out: just guessing: the $15 an hour minimum wage is sweeping the west coast -- and I am spamming the inarguable basics to every journalist and legislature whose address I can track down ...
... spammed 14,000 of simpler arguments about same all over country last year (took three months) so when it comes their way they will at least have the basics.

I figure that when the $15 minimum wage comes in to everybody's benefit in the west, it shouldn't take long to go in the east -- meantime it will be time to start pushing centralized bargaining -- once the possibility of real change reaches into the male pea brain (midbrain, limbic system).

I reading Piketty's magnum opus -- when I am finished (month or two) I will be ready to do a real zinger on the labor market overall.

Different versions of centralized bargaining can be found in continental Europe, French Canada, Argentina, Indonesia.

Final thoughts (one example) on the human male problem:
Show a human female that a $15 minimum wage will only raise overall prices 3.5% ($560 billion added to $16 trillion) and common sense takes care of the rest. Males need one more number (before they no longer obsess on the big pack outside): that the 45% of the workforce getting a raise wont be laid off -- wont be told: "we don't need your output anymore" -- over a small price increase.

[ADDENTUM: The Teamsters Union has a version of its own: the "National Master Freight Agreement" -- or else Teamster truck drivers and warehouse workers would be as poor as regional (half the) airline pilots. I was a member of local 804 -- Ron Carey, local president (later national president) -- just a warehouse worker pushing and shoving furniture (didn't get my driver's license till years later; New Yorker). Last I heard, some years back, 804 raised its defined retirement benefit (all securities kept under ownership of the union) from $3300 to $3600 a month.]

[ADDENDUM II: "The White House’s “My Brother’s Keeper” initiative is destroying the Black Male Mentoring Movement — decades-long work to save Black boys. Virtually all of the small, community-based agencies that comprise this substantial, historic effort to mentor Black boys have been left out of the overall conversation, the planning, and the funding ..."  [emphasis added]