I have not seen any significant startup time differences between 4.2 and 4.2.2 on any of the machines that I use (usually I get around 30 second startup, on Windows and Linux, though on my new quad-core box at home I am getting 15 seconds, Windows and Linux).
Look at the console log and see if there are any noticeable pauses between log events, that might help pinpoint where the issue might be. Usually on something like this I suspect network request timeouts. I don't know if 4.2 is making network requests that 4.2.2 no longer makes.
The delay seems occur on "SSL entropy generator".
I hope that helps.