There's no question that Legolas would have been an asset in a fight -- he was a great asset at the fight he was in (Helm's Deep). Shelob stung Frodo when he "lost his mind" and began running toward the pass that was the entrance to Mordor-proper. Thus Sam had to dispatch Shelob with Sting (an event nicely woven into the Hobbit pre-quel).
I think your point is well taken that had most any of us been faced with Aragorn's decision, we probably would not have had the "intestinal-fortitude" to let the fate of the ring-bearer take its course -- but would have either gone after Frodo ourselves, or sent other capables after him. I suspect that faced with a similar decision, we'd all do something different than Aragorn did -- hedging our bets if you will.
I've been searching through "The History of the Lord of the Rings" (by Christopher Tolkien) trying to find out how JRRT decided to have Aragorn go after Merry and Pippin instead of following Frodo. So far I haven't found any debate about it. I'll keep looking in "The History..." and in "The Letters" to see if I can find out.
What's interesting to me is that in earlier drafts when the Fellowship breaks, the orcs aren't there. Merry and Pippin just get lost and wander into Fanghorn and Treebeard. Legolas and Gimli head north (back home?) and in one version are captured by Saruman and in another meet Gandalf. Boromir doesn't die and he and Aragorn go to Minas Tirith where Boromir becomes jealous of Aragorn, falls further into evil, and does a Wormtongue. Poor Boromir! I'm glad in the end that he "kept his honor".
Off to more research!