The fact that you don't get different seeds is arguably something to mention in the help files.
One thing is that this is not a real feature as I see it, because you can't really control the number of [random] objects that were created before opening a particular patch.
On the other hand, I can't believe people do rely on a [random] object giving the same output every time you open the patch. We have it in the documentation that using 'seed' is what you need for this and this is the only thing that can actually be done to guarantee the same sequence.
You can use externals like zexy's (ELSE also has [datetime] because someone requested) but if yo're gonna have to use externals, you might just end up using an external for a random number generator that has this function built in it already, and ALL random/noise generators in ELSE do this.
I don't think this will break anything but worst case scenario, we can have those 'compatibilty flags' IOhaness is not much a fan of :)
Vanilla could also have something like [date]/[time] one way or another, but adding it just for the case of managing seeds in [random] seems like a bad idea to me.
cheers