You know, because of the 5/22/13 Patch update featuring Dash and Shield Bash.
The shield bash can stun enemies with whoever you run in to. However, this also stuns opponents. The stun vial, when thrown, also is used to stun enemies from a far. The core element here is stunning opponents.
Essentially, isn't Shield Bashing into opponents like carrying around a stun vial that never runs out? As far as I know, I can stun Vanaduke for quite a bit.
Also the stun lasts longer.
But this should probably in the sticky for the 5/22 update...
Shield bash is actually quite dangerous, as you can still be hit while bashing, and if you charge head-on you can be pushed into traps by monsters. For a large group of monsters it is much safer to use the stun vial.
Stun vial has much more knockback, doesn't throw you into danger, and has stronger stun.
Stun on anything has not lost it's value. Quit attempting to stick your (redacted) view in our faces over a (surprisingly fairly balanced) new mechanic. We don't know the full implications of the update because the metagame has yet to completely catch up. In other words shut it and go grind some more fsc ya vogs.
Come back in a week or so and check how many threads pop-up whining about the mechanic in ld, if none appear then I feel this update will have failed :p. Elsewise it is just fine.
No they are not useless they still have range and don't use shield power