The clawshot and hookshot are very similar to each other. I'd argue the reason the grappling ability was discarded was due to extra potential strain it may have put on the player's wrists, having to flick the Wii Remote Plus, as well as the inclusion of the whip in the game which largely performs the same functions. The beetle, on the other hand, effectively replaced the boomerang and most certainly was a more versatile tool.
I have absolutely no gripes with Skyward Sword's item inventory. It's not my favorite Zelda game but it nailed that department perfectly. The Adventure Pouch added an extra degree of realism and hte items were varied as well as used throughout the course of the entire adventure.