You would think the easiest way to go about it would be to keep the economies of scale, that even the big capsuleer nullsec fights, while huge and violent, are nothing compared to the kind of resources and manpower an empire can bring to bear. It makes sense; the idea is that not many people live in nullsec but highsec is packed.
On the other hand, Empire fleets are built of titans that, for the most part, do absolutely nothing. Like American aircraft carriers, they're incredible force projectors that the country very rarely has to use and, if they do, they only need one or two.
In the end, I think CCP has to blame the difficulty of their game. Not that it's difficult, but that it isn't. Despite the PVP and logistics being as complicated as PVP games tend to be, actually floating in nullsec isn't difficult. It isn't like pirates are also constantly attacking capsuleer corps instead of being small cash cows, or that supplies are hard to come by once you put together one of those corps. The game isn't challenging the corps and forcing them to put their ships on the line, daily, just to "pay the rent" in terms of PVE.
I think CCP could make things more fun by making it harder to exist out there in nullsec. Force capsuleer corporations to either get supplies to operate from the empires, get them from linking up with a pirate faction, or make running an outpost station in nullsec so damn expensive that you WANT people to feel safe and secure trading there just so you can collect the tax money. And make sure that, whoever you side with, that you can have packs of roaming NPCs looking to ruin your day. Hell, to recognize the work that big alliances do, throw whole hordes of NPCs at them specifically, coordinating massive, custom attacks once every few months so that no one ever gets too comfortable.
Whatever happens, that ought to reduce fleet sizes a bit. At least there will be a proper drain on resources to justify all the building and logistics that goes into a nullsec corp.