I don't think there will be any non-trick weapons. There's a dedicated button for transforms/such weapons would be less interesting by default/it wouldn't jive with literally everything they have shown.

After giving it some thought, I think these are the base ideas in the weapons in bloodborne/how you would come up with one:

• Must have one-handed moveset for "base" form. This is why I doubt we'll see heavy weapons that have a further transformation - we'll have lighter, faster weapons that become heavier.
• The transformation needs to be significant and visible. The saw cleaver's transformation - slower and more range - seems like the minimally complex weapon.
• If a weapon needs "additional junk" to perform a transformation, it will be placed on the back of the wielder whole not transformed. This is important because you don't need to stick to entirely self-contained weapons.
• Other than changing the stats of the base weapon, the transformations seem like they can add new mechanics to the weapon (e.g., the rapier pistol).

Under those guidelines, I can think of three main categories of trick weapons in bloodborne:

• Weapons that transform into some sort of gun or gadget. We have seen this in the gun-rapier.
• Weapons that swap between two types of weapons - e.g., straight sword to hammer, dagger to dual wielding.
• Weapons with a unique mechanic (not in the above categories) that uses the transformation (logically possible, though we haven't really seen footage of anything like this yet the devs have mentioned the "pole weapon" that seemed to have a unique "set, fire" mechanic).

Under these guidelines, you can actually make far MORE varied weapons than in any previous souls title. Especially because any weapon can really be a combination of any two weapons in previous titles, or add arbitrary mechanics. Each weapon will take more work to make, and that might limit the weapon selection - but if From had ample time/resources to make as many weapons as they want, there could actually be MORE weapons than Dark Souls 2, all of them more interesting.

All that said, I don't think there will be weapon "classes" like before, and that's a good thing. Instead of having 5 "sword-hammer" weapons, I think there will be a much more organic blend of mechanics, and that will be great. Every weapon will feel unique and interesting. To this end, I think the upgrade paths will be used to differentiate the same weapon in different ways.