If you are having color issues you need to research and fix your color management issues or adjust the colors in your comp so they will compress properly. Highly compressed video streams are very sensitive to small areas of highly saturated color next to large areas on different color values. For example, it's almost impossible to get good solid red 255, 0, 0 against black 0, 0, 0 or white 255, 255, 255 if the red is thin text or lines and you compress the video.
If you are using the AME and the YouTube preset then you just didn't wait long enough for YouTube to process the 720p version or you did something with the upload settings. Sometimes it takes a few minutes for the HD version to appear on the server.
I never have these kinds of problems because I have established my own color management process for all my projects and I calibrated my monitor so I know what I"m seeing is what I'm really getting.
The current version of AE CC2014 is 220.127.116.11 so you should be using that because there are several bug fixes, or you should be on CC 18.104.22.168. Without knowing a lot more about your project than the color didn't turn out right and YouTube isn't displaying the HD version of my project I can't offer many more solutions.
Okay so what if from now on I pick a working space option under color settings while starting a new project and then choose my colors based off of that?
Then choose the matching Output Profile under color management in the render Que?
Hmm but even if that did work there are no Color Management setting when you send your project straight to media encoder and I will always have to send to media encoder because almost all my videos are made to go on Youtube or online somewhere...
What is your "color management process" can't I just copy those steps for all my future compositions?
About 80% of my projects are 32 bit with color space set to NONE. Some are set to color space profiles defined by my clients. Some projects are set to Display, mine is calibrated with a calibration tool - not by eye. My favorite is the X-Rite: EODIS3 : i1Display Pro. The color space you use depends entirely on the workflow and delivery specifications. If you loose the ability to set a color space anywhere in the project or are worried about that possibility then choose NONE. If you are sure you can maintain control, establish and prove your color management workflow before you deliver your product.
I'm also very careful with color values in my projects. Some things, like 100% red Helvetica at 40 pixels on a black or white background are going to fall apart when compressed or broadcast so you have to use values that will make these colors work. I do the same thing with gradients. A gradient that only changes color values from say 160 to 200 over an entire HD frame is gong to have banding with it is compressed to 8 bit, and if the gradient is moving it's really going to look bad and theres nothing you can do about it except add some noise or texture to the gradient to hide the 8 bit compression artifacts. Learning what will work takes time and experimentation. I've been doing this since you could have no values below 16 and no values about 235. We can use much more of the available color space but color compression and MPEG formats will always create color artifacts and change things if you are not careful with your design.
My color depth in my Project Settings is currently set to 8bits per channel (by default). Should I work in 32bits from now on during my compositions?
I work at 32 bit for most of my work because most involve lots of color grading and lots of simulated lighting effects. If you are not doing composites that require heavy manipulation of color and light then 8 bit is fine. If I was just doing screencasts or straight demo videos for the web I would probably work in 8bit, but if I were creating a FVX shot for a movie, which is most of what I do, then I would always work at the highest bit depth I could and keep all of my DI renders at 10 bit or better color depth. Your workflow depends on your design and your product.