The new look has a vast number of improvements and very few flaws. They've fixed a couple of these already: artifacts are darker (starting with Fifth Dawn) so they don't look white, and colored mana symbols in text boxes (like on Bringer of the Black Dawn) now have true colors.
I can read the names of white cards across the table in Limited. Power and Toughness are more visible than before. Longer card names are possible, more text fits in the text box, and the art is larger. Foils are superbly improved in appearance.
The new card face caused the biggest uproar in Magic history (second is firing Rebecca Guay).
Design becomes deprecated. It's inevitable. The Constitution needs amendments to maintain a strong and healthy democracy as times change (gays!! J/K). Circuit boards need redesigning to make use of better technology (this is my job ATM). Computer UI (user interfaces) need updates to better serve the user.
A good example that I'm sure you all know is
Nintendo controllers. Look at the old NES controller. Two round, cupped buttons (B & A), two horizontal buttons (Select & Start), a four-directional D-pad, all encased in a thin rectangular box. It's simple in design, yet effective.
Now look at the SNES controller. The rectangular case is now rounded off to fit in your hands better. The L and R buttons rest comfortably under your index fingers. The Start and Select buttons are tilted because your right thumb presses them from a angle. The Y X B A buttons are colored by pairs and textured differently (B A the same smooth cups, Y X are flat and slightly rough). They arranged in a cross so your thumb can press two of them at a time more easily (remember how we all held the old NES controller crooked while playing Mario to constantly hold B while pressing A periodically?). If you continue to look at more advanced controllers, you see they are less pleasing to the eye and more pleasing to the grip and function.
That's the real debate: flavor vs. function. The Magic card layout is a graphical user interface. It's job is to convey information about the card to you in an effective manner. R&D decided 10 years was long enough before a face-lift. Notice the GUI received small updates already with expansion symbols, card rarity, and collector's numbers.
All I can say is that I too signed those petitions and voiced my disgruntlement. But when you get down to it, you're still playing the immaculately elegant and infinitely deep game of Magic. It's just like a new Nintendo controller, sure it looks a little weird, but it makes the game play better.
If you just start playing with the new cards, you'll see that it's really just not a huge deal. I promise.