What I don't like the most about this update is the fact that the last time we had a full update was 5 years ago (1.3), and so far what they revealed about 1.4 isn't even close to what 1.3, 1.2 or 1.1 were, and those took about 2 years to release.
Considering that we don't know all the content that will be in 1.4, it's a bit strange to say that it won't be close to the size of those releases.
In the grand scheme of things, 1.1 wasn't really that big. It gave us all of hardmode, but it did almost
nothing for pre-hardmode. Overall, it gave us wiring, 3 new bosses, and a couple new biomes.
1.2 was bigger, in terms of how much it changed the world. But even then, 1.2 by itself wasn't all
that big. It gave us alternative things: different ore variations, an alternate version of the Corruption, an alternative version of the Underground (ice), and so forth. It gave us new visuals and painting, of course. It gave us early-game magic items, sure. 1.2 went wide with options, but it didn't really extend the endgame all that much. It gave us a couple of post-Mechanical bosses, those Biome Chests, and one end-game ore. It was only the later updates to 1.2 that gave us the many post-Plantera options like the Pumpkin Moon, Duke Fishron, etc.
1.3 was probably the biggest single update, giving us lots of stuff in every corner of the game: new bosses, new mini-biomes, a couple invasions, even more wiring options, and even more end-game gear.
Yes, 1.4 probably won't be as world-changing as 1.3. But neither was 1.2 and
definitely not 1.1. Even
just looking at what's already been spoiled, 1.4 is going to be more significant of an update than 1.1. Given the long time it's been in development, you may have forgotten just how much stuff will be in 1.4. Check out that Terraria Wiki page to refresh your recollection; it's probably more than you think.
The other thing you have to contend with is the fact that Terraria... is pretty full. 1.3.5 is a game absolutely overflowing with options from beginning to end. We have all kinds of weapons, armors with numerous effects, accessories for days, wiring options, and so many biomes that small world generation can barely give them enough room to breathe. There's just not all that much
room for more stuff. This goes even moreso once you decide that there can't be post-Moon Lord content.
So what's left? A few new biomes, a
major interface change (block-swap), adding a few bosses here and there, and smoothing out the item progression from beginning to end.
Also, the last time we had any update at all, even it being content not that relevant, was 2017, 3 years ago.
I don't know what is going on with Re-Logic, love the game since 2012, but overall 1.4 just seem lacking and disappointing for the amount of time they have been developing it.
What's going on with Re-Logic is that they tried to make a new game, and it didn't work out for various reasons. Even though they hired on other people to make the game, overseeing them took up time and effort that couldn't go into 1.3.6. If everything had worked out as planned, we would have had 1.3.6
and Terraria: Otherworld to play. But because it didn't work out, we have neither.