The reason 2.x seemed to have way more content than 4.x is because 2.x was mostly riding on the coattails of 1.0.
They were able to release 3 new trials, 3 new dungeons, a plethora of new side quests and QoL improvements because a big part of the content back then was stuff from 1.0 repurposed to fit in the new version of the game, while the other portion of content was either stuff that was already in development way before 2.0 had even been released or it was things using old assets so it wasn't exactly that much of a challenge to make.

Now that we're in patch 4.3 there's pretty much nothing left to "recycle", as it were, and all the content we're getting is 100% original and built from the ground up. This is especially noticeable in the dungeons, go back to the ARR dungeon list and look at how many of them are hard modes which are just reused assets from the original dungeon with new enemies and bosses, there was pretty much only one completely new dungeon per patch. Meanwhile SB so far has only had 1 hard mode dungeon (about to be 2 in 4.4) with every other dungeon being completely original and with much higher production values. I don't mean to undermine the developer's work however it's clear a lot more effort was put into Swallow's Compass than Snowcloak just in terms of design, for example.