Well yes, since you asked. A 12V power source is generally shown with polarity marked. Your 12V source has both leads going to (+) pins which as I am sure you can imagine , begs the question " since when do 12V power sources have two "+" leads. I'm sure you have an explanation but whatever it is , if you submitted that schematic to an engineer in a company he would reject it and ask you to label the + and - terminals of the battery (or power supply) and if possible explain why both leads go to + pins.
Also, engineers prefer to see the GND symbol at the bottom of the schematic , not at the top. The convention is + power (Vcc) at the top of the page and - (GND) at the bottom. Is there a reason why you din't number the pins of the display and the chip. This information is on the datasheets. The arduino doesn't need it because it's silkscreened on the PCB. If you want us to be really picky
I (personally) would object to labeling the arduino connections as "pins" because everyone who knows anything about it knows that the I/O names D1,D2,D3 etc are not the same as the ATMega328 chip pin numbers and these days , many people prefer to buy just the chip for $5 and breadboard it or mount it with a socket in a RadioShack pcb rather than spend $30 for an UNO. If you want to avoid confusion you can use the generic d1, d2 or D1 ,D2 (short for "Digital Pins. If you used analog pins they would be A0,A1 etc.
