First a bit of a disclaimer: I haven't nor will I likely be running around in a destroyer ganking hulks or any other type of mining barge. I do appreciate the hard work those who play like that put in for the saving and conservation of our precious asteroid belts. Indeed I don't 'often' find myself mining, but I do feel the impact of minerals as they end up costing my pricey pvp habit to become even more pricey.
It seems that some of the inner workings of the balance thoughts for the new barges has been revealed and shared with the community through this devblog.
Now in looking at some of that information we can surmise that CCP has stayed largely true to their vision of what the three turreted mining hulls will be doing.
My impression is that the Skiff and the Procurer will be the tank heavy, dangerous space, solo mining poster-child. Now if only lowsec mining was worth a damn to entice people out there to do some procurer or Skiff mining! As a side effect of this buff these two ships will be massively difficult to gank, but the bigger tool theory does still apply, obviously the money spent will no longer be slanted so heavily in the favor of the ganker.
Next up are the middle class of mining barge, the Retriever and the Mackinaw, and what will probably still be less used than the Hulk/Covetor. These are going to be more solo-mining ships, with massive newly minted ore bays that will hold either equal to (Retriever) or more than (Mack) a jet-can. This should allow solo-miners to have the ability to mine peacefully in highsec, less worried about barge gankers and unworried about can flippers because they will not have to drop a can if they don't want to.
The Hulk and the Covetor retain the title of the biggest yield per hour, but now lead the way in both Ice and ore m3. However, they have the lowest EHP, and lowest ore hold, so really these ships should be used when mining in a group, preferably with a Orca or Rorqual on hand for support. Now I say "should be" because let's face it, it will always be about the isk hour, and when isk hour can be directly correlated to m3/hour.... then the Covetor and Hulk are still the masters of that domain. Jet can mining will still be a viable alternative for this pair of ships, but they will still provide the largest isk/risk conversion.