Though at this point I feel like I seen all that Terraria has to offer.
Mm... then you've missed some things. Pbat's seen,
maybe, 3/5ths of the game's content -- likely 2/5ths or less. He's hit a lot of high points in there, but there's a lot that's still missing -- at least one boss-style encounter (the goblin invasion), 2-3 biomes, and I'd estimate anywhere from 2-4 tiers of items. Plus he didn't really do much in the way of thorough investigation on any of the item tiers he
did hit -- we've not seen demonite armor or meteorite weapons, ferex, nor anything that might involve ash or hellstone. We know there's a number of items still unseen from Pbat's angle that can change things around -- the vine grapple, necro armor, and jetboots are just a start. We don't know what kind of special items come from iron, or copper, or gold, just the standard tools and weapons. We haven't seen what happens when a solid game of PvP goes down, nor how the game reacts to large-scale construction, if it does at all. From Pbat alone, we haven't seen much construction at all, really. I don't think he ever even used a platform, much less saw if putting candles, books, etc, in buildings has any effect on the game. Dominic is illuminating that aspect a bit, though.
Above and beyond that, word from the devs is that content above and beyond everything P's seen is streaming in constantly -- from what I understand, they're basically just twiddling their thumbs waiting to get some legalities and infrastructure in place, and Redigit's way of twiddling his thumbs is coding up oodles of new junk to throw around. So content is, even now, expanding.
We
have seen enough to get a good feel on how the general game goes about, though, and it doesn't seem that the extra items are going to radically change that -- so in that sense, we've seen at least the structure of what Terraria offers, if not all the particulars yet. I can see how the feeling would come about, yeah, though for me it's just whetted my appetite for the full course