Terraria does have a lot more content than Minecraft, for sure. There's no denying that. It also has a lot of different KINDS of content. Interior decorating is actually a thing in Terraria! Chandeliers! Tables! Chairs! Statues!
Terraria exploration is still more rewarding, in that you get more Cool Shit. Grappling Hooks! C'moooon. It absolutely would not hurt Minecraft to have more stuff like that. I want to go underground, find a mushroom jungle, kill a giant demon eyeball, get a wand that shoots fireballs, and then go back to the surface and build a skyscraper which reaches a floating island, atop which sits a chest holding rocket boots, and then jump down from way up high and not take damage because I'm wearing an amulet that prevents falling damage, and then kill a bunch of zombies, and use their rotten flesh to build a pet zombie* which I can summon and desummon at any time for kicks, and then build an army of them, and go storm my friend's castle with said zombies, and and and
I mean, why not?
That all said, I still think Minecraft is a better game, simply because it's 3D. Exploring in Minecraft is more about finding those cool-looking areas than finding cool toys. That extra dimension adds so much. I really can't trade it away. I like Terraria a lot, but I can't stand on a mountain and look out on all my creations from a distance. Still, I wish Minecraft would have more stuff like that.
*at this point i just started making shit up