Tomorrow small and medium rigs are coming to eve, the former for Frigate and Destroyer sized hulls and the later for cruiser and battlecruiser hulls. The mediums will be 1/5 the cost of a current rig and the smalls 1/5 the cost of the medium version (at least, that is what the devs are aiming for).
So, who's the big winner here in terms of ships?
Think about it for a second, I'll wait.
If you said Tech 1 frigates you're wrong. Rigs might make a couple of them tougher (punisher) but they are still relatively small and fragile. Its just that 30% more armour is not much when you only have 1000 points to begin with. Tech 2 frigates will benefit more but since they only have two rig slots it won't be earth-shattering.
Destroyers will get more benefit than frigates but still suffer from the fact that they are fragile and the rigs won't improve them dramatically. T2 destroyers again get more bang for buck but are still relatively fragile and again, only two slots.
With cruisers we are seeing more benefit as they have more hitpoints, weapons, and rig slots to take advantage of. A rig worth 2-3 million might not be a bad idea on a tech II outfitted cruiser. Most Tech II cruisers are rigged already by default so they will simply see it as a cheaper activity instead of a big boost.
No, while all those ships will see more rig usage they are not the big winners here. Battlecruisers are.
Think about it: many people rigged battlecruisers already but it was often a choice that cost more than the ship and fittings combined. Now it will be a small fraction of the overall cost. Plus, since most (all?) rigs are percentage bonus based and battlecruisers have the largest starting hitpoints, number of weapons, power grid they will get a larger bonus from the rigs. Command Ships, like Tech II cruisers, are probably already rigged by default now so again it will just be a price reduction for those pilots.
Yes, Battlcruisers are the big winners of this change.
As a collary to this post, I expect demand for the small and medium rigs to be very high, salvage will be drained from normal large salvage production to make smaller rigs, and as a result all rig prices will be starting high or going up until production can match demand.