Return of Reckoning

BLOCK
I did some fairly extensive testing to determine exactly how Block works. These are the conclusions drawn from the results.

Against 1H melee weapons (eg. dual-wield classes, s/b tanks, etc): block % = (20% x block rating on shield / opponent's offensive stat) + 10% +/- other % modifiers

Against ranged attacks (magic abilities of casters, SW/SH/engie's bow/gun abilities and auto-attacks): block % = 20% x block rating on shield / opponent's offensive stat +/- other % modifiers

Against 2H melee weapons: block % = (20% x block rating on shield / opponent's offensive stat) - 10% +/- other % modifiers

With regard to the different weapon types, when it comes to calculating block %, it appears that

1H melee weapons are:

1H melee weapons such as swords, axes, choppas, etc used by the melee classes including mdps and tanks. (I didn't check if this applied to the melee weapons of engies, SWs, and SHs, but I would be surprised if they are not also included in this category.) WHs executions are blocked at the same rate as the class's sword attacks.

Staffs that casters use for their auto-attacks. (Although they have the stats of 2H weapons, the block % versus these weapons receives the same + 10% modifier that 1H melee weapons receive. If you watch the aa animations for these classes, you'll find that the staffs are used in one hand (except for rune priests). I guess that's why they are classified as 1H weapons for this case.)

2H weapons are:
2H weapons used by the melee classes including tanks.

Ranged attacks are:
Magical attacks of casters.

Bow or gun abilities of engie, SW, and SH, including ranged auto-attacks. I didn't check the melee attacks of these classes but I would guess the "block% versus 1H melee formula" will apply to the attacks of these classes when they use their respective melee weapons.

There appears to be a lower limit for block % versus a 2H weapon of about 2.5% + other % modifiers. The -10% modifier doesn't seem to be able to reduce block % below this 2.5% value.

The maximum value that the (20% x block rating / opponent's stat) term can supply seems to be capped at 25%. But Bruglir stated stated in his post in the General Discussion forum that the cap is 50%. The block ratings on the shields are too low for me to test this further with my level 10 toons. Perhaps someone could test this with higher level toons that are at the same level by having a heal-specced AM, etc use their attacks against a tank that has a shield with a high block rating. (Also, there might be lower cap for lower level toons, 25% at level 10 but increasing to 50% at level 40.)