The reason we do it with preseeding rather than by run-time detection is because otherwise the server kernel ends up being installed for *all* PAE-capable machines that perform a netboot installation, which I don't think is appropriate. Unfortunately you can't assume that the -server kernel should be used if it's available and the system supports it, otherwise this would be a lot simpler.
We need some way to select the -server kernel if the system is capable of it, if it's available, *and* we're installing from the server CD. Right now, there's no mechanism that would permit this, so one would have to be invented.
The reason we do it with preseeding rather than by run-time detection is because otherwise the server kernel ends up being installed for *all* PAE-capable machines that perform a netboot installation, which I don't think is appropriate. Unfortunately you can't assume that the -server kernel should be used if it's available and the system supports it, otherwise this would be a lot simpler.
We need some way to select the -server kernel if the system is capable of it, if it's available, *and* we're installing from the server CD. Right now, there's no mechanism that would permit this, so one would have to be invented.