Oh wow both styles are actually really pretty!!! Honestly if I were reading the comic, I wouldn't have a problem with this... it doesn't seem like that much of a drastic shift to make people question anything. Speaking from experience I mean.
I recently changed artstyles for mine, although I chose to incorporate it into the storyline as an attempt to let people ease into the change a little more (one of my favorite comments is "You deYASSIFIED him!"). The artstyle is a little more mature as well, symbolizing that the main character is growing-up (Naota is becoming uncomfortable in his skin).