Since you asked.
#1 there isn't enough room for a trackball, you need a minimum of 3-4 inches in every direction clear to use a trackbal properly.
#2 You have put worthless mouse buttons on the right of your trackball which woudl have gave you that 3-4 inches I was tlaking about. Your tb is right against p1's button array so you could have used buttons 1-3 for the games like missile command ect. Those three buttons just add to the clutter.
#3 You have 8 buttons per player for player 1 and 2. What are those for? No mame games use that many buttons plus a joystick and I don't see any consoles hooked to your "cab." This one is subjective so I'll let you get away with it.
#4 Your layout doesn't put the start/coin buttons exactly a certian distance from their respective controls. This isnt' necessary, but it a courtesy thing for your guests so they dont' have to reach in front of you to press start. also it looks much nicer.
#5 All your buttons are crooked. This is probably due to you figuring out you wouldn't have enough room after you cut out the panel.

#6 Your panel is curved towards the player. Regardless of the fact that I'm sure a lot of people catch their hip on those corners, the way you have it cut out poor player 3 and 4 have a tiny little trinagle to rest their hands on. If you would have taken the smae panel and flipped it around it would have done much better and looked like it actually belonged on an arcade cabient. I agree with the last post, that doens't look like it belongs on that cab at all.
#7 You have 6 buttons for player 3 and 4. What are those for? There isn't a single 6 button, 4 player game on any platform, so those are just uselss.
Note: Beyond this point is artwork critiques, as this is subjective I normally don't comment on this, but since you volunteered yourself.
#8 Your cp graphics don't have any theme or coheriance what so ever. They are drawn in different styles, they have different color palletes, and they are a different size.
#9 All of the characters are looking to the left. Making the ones on the right side look t the right would have made all of teh difference in the world.
#10 Your graphics aren't spaced out evenly, and by evenly I mean blancing the stuff on each side.
#11 Your graphics are very very bright, but all of your buttons are black. If you would have allowed the characters to be partially covered by the controls, or used matching buton colors this would have worked great, but as-is they are kind of floating there on your plain blue background.
But I would like to point out the things you did do right for fairnesses sake.
#1 You button configurations are standard, the buttons are close together and they are clean and matching. This type of stuff if often overlooked byt eh people here. It looks very professional when the buttons are in tight configurations and very amateurish when they are spaced out.
#2 You have the proper amount of blank space on your panel. It may not be in the right places, but at least you didn't make a 6 foot panel for 2 joysticks and a button.

#3 Your overlay and panel box are nicely finished. It's very clean and professional looking. I really wish more people would take the extra time to finsh their projects like you did. Now the character arrangment and choice are another thing, but at least you didn't try to put 600 characters on the panel or take every single mame marquee and make an overlay out of it. Overalys should look more like this and less like an ugly mess of random objects. I saw some sideart made out of cahracters that someone did a while back, I won't name names, but it was an example of what not to do.
Oh and for the guy that questioned my credentials, I've been in this hobby building panels for 5 years. When you have that much flight time then you can question me.
