For me,there hasn't been too much of a complication.Once everything is networked it presents few problems. I think that's chiefly because I really prefer to maintain a hardware approach to this.Like you said, MIDI over LAN is probably not quite there yet, but a combination of it and the hardware is more than adequate.
I no longer use hardware effects: the only related hardware I now user is an Avalon and DBX Quantum. I rarely use effects on the slave machines, with everything coming up in Logic from the slaves I have more than enough effects,both Logic and third party (like Altiverb and Powercore Firewire, etc) to cope with any contingency. Also most of my stuff is orchestral orientated,with the electronics in a supporting role.
I don't like freezing tracks either. I prefer to have immediate recourse to sounds that can be altered. With a multi computer setup one can achieve this easily.
Logic on two machines would be nice for those who wish to run more EXS's, but I'm currnetly happy using it on one,and I have Kontakt 2, which is more than adequate for a similar purpose. My EWQLSO is spread over the three Macs and the Receptor,divided into sections (strings/brass on two machines, woodwinds/percussion on the other two),whilst the PC runs VSL on Giga,along with other stuff like VOTA. I also have other stuff,like Atmosphere,Stylus Korg Legacy, Albino, Absynth,and the East West, Symphonic Choirs,RA, Storm Drum. The usual suspects. hey are spread over the system equally, and I have found that it all seems very smooth.The whole thing is controlled from a single Logic Control. I ditched my 02R96 some time ago, and never looked back.
Regarding Kore. I'm very confident of its power and ultimate reliability. It's basically, performing the same function as V-Stack, and then some,so, the bottom line is it's going to be at least as good as that. I do like V-Satck a lot: its simplicity and value for money.It's just that it's become cranky under Tiger,and Steinberg's support is practically zero. Kore will have a nice hardware controller, too, and will run inside and out of Logic. It's a beast.
Filewise, outside of Logic, the setups are simply saved as the project's name (Cue,timecode reference) and put in an appropriate folder. It's that simple.They have no direct dependance on Logic,so there is no requirement to do anything other than save and back up.
I hope that helps. For me there is currently no better way of working with large-scale arrangements and cues,than with multiple computers,though I still use a few hardware synths. I do not use Pro Tools, and cannot really justify it in my methodology. It would be nice one day,though, if there would be a computer so powerful that all we would need one of it to run everything. But we all know that ain't going to happen.