Is it possible that there are still good openings that remain unexplored?

Kids aren't always right, you know.

It's not necesarilly bad.  Earlier today at the Denker tournament in Tampa, I watched a 2300 player do exactly that.  He used a King's Indian Attack setup, which often has a knight on d2.  But what was new to me was that he placed his other knight on the e2 square instead on the usual f3 square.  So whether is is good or not of course depends on the specifics of the position.  There are guidlines in chess, but these guidelines are somewhat flexible, which allows creativity.

It would be awesome, but with all these years of Masters studing chess all day and all night, and now computers, I really doubt it.

If you like that set-up you should read Suba's book on the "Hedgehog" which well explains its strengths and weaknesses, and gives good exampaes of how the play can go.

1-e4, c5 2-g4 Sicillian defence, Grob variation.