We can debate about this, for example, Arm's Length. Is it really important? I don't use it, and I don't die on Tidal, and even on the Tornado spell (sorry, I'm not english and I don't know the name of all Shinryu's abilities) it's not a good idea, since sometime you're linked with another player and it's the last blast that makes the chain break.
Also, I'm using a SAM with the Sks very high, and I just need Invigorate. For Goad, it's important since, as you said, an error can come quickly, and it's helping a lot a player, even during AOE phase (SAM again, but MNK too, and BRD too!).
Second Wind saved my life a lot, if I'm too far from the healer for X reason, or the healers are overwhelmed. Or just, not enough HP to survive to 2 attacks.
However, without that, we can see we haven't a lot of usefull skills. Arm's Length is interresting, and I really love Feint since SB has been release.
I really think cross-role abilities is a bad idea. It's useless, and most of these skills should be added to all jobs that are linked too, it will avoid the "Do you have Goad please?" "No lul" event happening in Raid/ Dungeon.
Same for Shirk, or those who use a slot for Ultimatum...