This is why you see me stating time and again that the industrial capacity of the enemy nations should be included in the win the war requirements. No, it won't stop the horde from doing the hording, but it will take us away from the, "Capture X number of each nation's bases and you win the map." routine, and maybe give us more fighting across the map. It'll be, "Capture x number of each nation's bases and reduce each nation's strats to less than 20% and you win the map.".
Also, the inclusion of HiTech's Concrete Factory that affects the town's down time in their respective zones and Railyards that affect the spawn time of the AI supply convoy's in their respective zones, could prove to be helpful in some form or another.
I remember reading in a topic somewhere that Towns actually had puffy over the field in the past. So bustr's idea to bring it back may help in this as well. If they brought back the zone base system (while keeping the Capital), those key bases you are talking about bustr, could be the modified (key) bases with the beefed up requirements to capture. This could work out nicely as well.
Using Compello as an example:
There are 4 Zones, 1 on X side, 1 on Y side, 1 "in the middle" and the Capital/HQ zone (or maybe just 3 zones, in which case you just eliminate the "in the middle" zone). To win the war, you need to capture 20% of each side's bases, INCLUDING capturing the zone bases (which will not be included into the percentage required for bases(?) This may make it TOO hard to win the war at which point, having them as part of the 20% would be acceptable) in each zone AND reduce the industrial capacity of each nation (all strats, concrete factory and railyards included if they are added) below 20% to win the war.
For a small map like Grinder:
The industrial capacity requirement remains the same. There would not be a Capital, but the old strat system layout, scattered strats with the City near the HQ, and the others not so close to the front to where they would be surrounded by bases taken, with 2-3 zone bases (1 zone base towards each front and possibly one near-ish HQ). Or, the Capital stay's and just make 2-3 bases a zone required base (which would be the easiest to implement).
This MAY thin out the horde, but probably won't. However, we are likely to see more fighting across the map vs the usual bottleneck fronts we see.