Either it's a quite small team working on this game or there is something else wrong, because I have to agree with the OP, development time compared to the achivements is kinda long.
So what games have you made that makes you qualified to judge the work being put out by a software company? I mean I wouldn't critique a surgeon on his technique as i'm not a surgeon.
Also these are just the confirmed changes, every update there is always a lot of surprise features that they don't tell us so there is some surprise and excitement.
Vehicles Overhaul
+New Physics
+New Vehicle: Bicycle
+New Vehicle: Motorcycle
+New Vehicle: Jeep
+New Camera Controls
+Shift button to increase Torque on Bicycle for uphill speed
+Space bar to bunny hop on Bicycle
+Jeep can damage blocks.
+Steering using the mouse 2/12/18
Sleepers 2.0
+Vulture Sleepers
Dungeon POI 2.0
+Environmental Hazards
+Zombie Closets
+Climbable Trellises and/or Vines
+Backstories for many of the POIs
+"Helper Blocks" that visually show whether containers are empty or lootable
+Random loot containers to make each POI unique for where loot may be
+More than 70 new POI's that have been level designed 4/14/18
Player(Bandit) Motion Captured Animation
+Separate male and female movement styles
+Players now look up and down and always appear to be breathing
+Combat movements including power moves 2/21/18
Weapon Overhaul
+Replace gun parts with attachable modifications, compatible with buff and skill frameworks
+Whole guns instead of parts in loot containers
+Weapon quality determines how many mods can be attached
+Mods won't have quality tiers. 3/21/18
+Removing a mod may not be possible....still in development
+Size of crosshairs accurately reflects cone of hit probability.
+All mods use a single item id# but allow for 30,000+ variable mods possible
+Power moves for melee weapons use the right mouse button and expend stamina 2/21/18
+Weapon sounds tagged to animations to better maintain sounds syncing correctly 2/21/18
+Perks and skills and buffs will affect various aspects of each weapon 2/21/18
+Weapons can be crafted at workstation. Mods added through assembly interface 3/20/18
+Mods won't be craftable. Obtained through scavenging, trader, and quests 3/21/18
+Weapons can be tinted to other colors using up a special tinting mod slot 3/28/18
Buff Overhaul
+Replacing old buff system with a more robust and optimized framework
+Designed to work and stack with blocks, items, weapons, clothing, skills, perks, and attributes
+Can be triggered and modified by events during a buff's lifetime.
Progression Overhaul
+Replacing old skill system with a more robust and optimized framework, also designed to work with items and buffs.
+Character attributes added to better create classes and differentiate play styles.
Integrated Survival System
+Changes to how health, stamina, fullness, and hydration will work
+Hunger represented by reduction in stamina max. Eating restores max 4/14/18
+Thirst represented by recovery rate. Higher thirst means slower recovery of stamina and health 4/14/18
Quest System
+Cool new group quests
+Dynamically spawns a boss to guard quest objective
+Dialogue system that is fully moddable 3/5/18
+Trader initiated quests 3/5/18
+Quests and quest POIs will work in Random worlds as well as Navezgane 4/19/2018
Stealth System
+New Stealth related display bar with as of yet unknown functions.....
Terrain and World
+Distant Trees 2/12/18
+POI Editor accessible in main menu
+Terrain Editor accessible in main menu 3/20/18
+Navezgane terrain vastly improved 3/20/18
+New Height maps for interesting cliffs, ridges, and better variety 4/14/18
+Random maps will be pregenerated to load as fast as and play as optimized as Navezgane 4/27/18
AI and Pathing System
+Zombies scan obstacles in 3 block height and target the middle block followed by bottom then top blocks depending on block hp 4/19/18
+Zombies prioritize obstacles according to block health. 4/19/18
+Game scans terrain for multiple pathways a zombie can take after any change. 4/19/18
+Turn smoothing and prediction added to reduce appearance of zigzag grid following 4/19/18
That's not counting the myriad of improvements such as the upgrade to unity 2017, the fix for large map jitters, the huge amount of behind the scenes work to the xml opening up powerful new features for modders and laying the groundwork for more changes, sticky arrows, etc
