There's a very good article about yacht racing rules on the Vintage model yacht site - just google "1730 rule". The rating of the hull equals (LWL+Beam)squared, times Beam, divided by 1730. (feet for full size, inches for models) From which you will see that beam is penalised relative to length, so boats like Foxhound were 40ft lwl and under 6 ft beam. All that would keep them upright was a ton of lead downstairs, and there were no restrictions at all on hull depth or rig. In the context of the rig, remember Dixon Kemp's words - "I do not consider that a craft, of which the boom does not extend considerably past the taffrail, is a sightly craft."
That isn't a box aft - its a bit of wood taped over the rudderhead to keep the water out. This boat has never really been finished, but I've got a sail servo for her now and maybe sometime I'll get around to her.
Why such a deep body? Simplicity of construction. Half inch plank oval for base, ditto but hollowed out for deck "framing", wrap some ply round the and BYU. There is no internal framing whatsoever.
Drop keels - yes they did drop off occasionally, there not being much scope for athwartship triangulation within the hull. The boat then floated for a short while on its side. Of course, because of the max beam (excluding chainplates) rule there was not much scope for flare and reserve bouyancy, so they tended to go straight through waves rather than rising to them. This was all very well so long as you'd remembered to batten down all hatches companionways etc. I think the mortality rate of yachtsmen had a great deal to do with the change to the LSA rule.
Yes I think the class should be revived - I do accept that POETRY is a rather extreme design (happening?) but she fits the spirit of the rule.