In my current "sandbox-y" campaign, the starting map of the area featured a red dragon in the SW corner - not as a decoration, but as an honest and accurate "A red dragon lives here and terrorizes that area." The party is now 9th-ish, and haven't even stepped a foot in that direction.
When they were around 6th level, they acquired "The Shield of the Guardian". It's a +1 magic shield, that can glow with a soft light (candle, 5' bright, plus 5' more dim). It was carried by a knight that protected the refugees on a decade-long flight to safety. No one recalls his name, just that he was always the one riding to the rescue of the civilians when ambushed or flanked, prioritizing their safety over his own. And eventually, he fell in battle, saving those civilians; the shield was lost for centuries, but his story lived on. Until the PCs found the shield, hung over a mantle in a hobgoblin barracks, as a war trophy! (Mechanically, when the shield is glowing, it slightly incentivizes "random target" situations to pick the wielder. Like "1 to 5, the ogre attacks the knight, 6 to 10, he attacks the rogue" becomes "1 to 6, knight; 7 to 10, rogue". All from belief in the story of the Guardian Knight.) The PC knight who carries the Shield now had a brief side-encounter with a dwarven historian that recognized the crest, earning a small boon from the scholar because "the Shield wouldn't allow a bad sort to wield it" [not true!], which cemented some of the story. The party tank has carried that shield ever since.
In a previous 2e campaign, the 0th-level characters acquired "the Sword of Othalgar" - from the ruins of Othalgar Keep - which was a +2 magical longsword that would return to your grasp when summoned. [And yes, the paladin did dispatch a BBEG later in the game by punching him in the stomach with her empty hand... and summoning the sword! with a nat20, no less!] The point here being "wow, powerful sword" but also it was a well-known sword. Multiple plot impacts happened from them visibly carrying and using the sword, from theft and assassination attempts, to purchase / inheritance claims, to back-taxes, and (by the end of the campaign), two of the PCs becoming the new Lord and Lady Othalgar. (Inheriting the Keep, and the border responsibilities that came with it.)
So "is a +1 sword enough of a hook"? As so many have responded across 13 pages already: depends on the players, and depends on the sword! What's the STORY that supports the HOOK? The "+1"-y-ness is just the loot!
