Templates indicates to their consumers that they represent best development practices. This puts a certain burden on the quality to the templates. Unfortunately the PDE RCP templates in Eclipse 3.5 were all based on actions which I believe are superseded by Eclipse Commands.
I have seen in the past lots of questions regarding actions in the Eclipse RCP and PDE newsgroups. I believe that at least some of these questions are based on the fact that the PDE templates still promote actions.
It also looks good for the mail example. It seems that work is happening in Bug 253105
Actions are (a little bit more) dead. Long live the command!