1) Up the maximum memory limit on RAM to 8 GB.
2) Make sure new iMacs are preloaded with MacOS X 10.5.2.
3) Provide a better keyboard (the current iMac keyboard doesn't look like it's comfortable for long-term typing).
I agree.
2) Make sure new iMacs are preloaded with MacOS X 10.5.2.
They will as soon as the OSX.5.1 versions already in the pipeline are sold out the spigot. If you buy your iMac at a Apple Store, they will upgrade it for you for free.
3) Provide a better keyboard (the current iMac keyboard doesn't look like it's comfortable for long-term typing).
I disagree. I bought one of the new keyboards for my G5 Tower and it is wonderful to type on. It is very comfortable and easy to use.