I'm new to the forum, but I've been playing the game for about a month now. I see a lot of potential for this game and so far I'm really liking it. I know it is in Alpha stage and things are still being implemented so I wanted to throw my thoughts it as well. I'm sure some if not all of these have been said before.
Animals
I would like to see more animals, such as: dogs, cats, lions, wolves, horses, mules, raccoons, squirrels, mice, turtles, snakes, frogs, maybe some insects, lizards, panthers, etc.
I also agree with a breeding system.
One thing though that I think would be really nice is animal companions. Maybe even if you tame lets say a wolf they would even fight with you if you are attacked. (Read that monsters were gong to be added!)
I do like the idea of being able to choose what animals are in the campaign, I think that would be good for the monsters as well. Say you want to go all out fantasy, or perhaps lore, or maybe even just supernatural beings. I would like to be able to hunt down Bigfoot. Just saying. Maybe even adjustable scales for each one. Like say I only want one Bigfoot, but a ton of ghosts, as an example.
Oh and if you do add vampires and werewolves, I want to be one if I get bitten! 
Especially if there are NPCs!
I don't know if it is a glitch or not, but I died once and came back as a ghost (however I didn't spawn as a ghost, someone hid my body and then I was a ghost).
NPCs
Some villages out there to raid or trade would be fun. Maybe they could be different types such as friendly, aggressive and neutral.
Blocks
I saw somewhere that the blocks were going to be fixed so that two triangle can be placed together. I'm rooting for this. I'm also hoping that you can build on top of a half block after that fix.
PnB
Sad that the plugin doesn't work. Just want to say yes please!
Different shades of glass.
Different cuts of windows.
Circular and oval wood.
Carry
Backpacks! Craftable carry would be very nice.
Snow Biome
It's kind of a boring biome. I think if even the cold affected you that would make it even better.
Player
Temperature affects; clothes and shelter can help if too cold... or too hot. Maybe getting sick like if you are in the rain or cold too long, and definitely more status affects. I think stamina was a good idea, however recovery is too quick. Maybe logging and mining could also take down your stamina, and effects you less if you are using better tools.
Sleep is something that has to be done instead of just used to pass days.
Less or More
Adjustable resources, I know you can do that with ores, but with animals and vegetation would be nice too. Currently it doesn't feel like it's too hard to survive with a ton of animals and plants.
Weather
Tornadoes, Hurricanes, Tsunamis, Earthquakes, Dangerous thunder storms, I don't know if there is lightning, cause I haven't seen it yet. Volcanic eruptions, don't know if that happens either. I heard there was lava, haven't seen that either. Whirlpools, dust storms, you get the ideal. Although they should be able to be turned off and on.
Water
Rivers and waterfalls.
Life and fishing!!!
Transportation
I know cars and trains are being added and I believe horses, but I would also like to see boats.
Structures
Other structures to explore besides cabins and dungeons, maybe like old ruined villages, temples, or castles.
Campfire
Has to be fed fuel to stay going like the furnace, or really anything that has a flame.
Caves
OK caves are the one thing I don't like that much. Most of the ones I run into are a deep black pits of death. Some I can get into without a problem, but I have to say at least 90% of the time I have to do a lot of work to get in them. I wish they were more linear, but with some depth, instead of mostly depth.
I know that was a lot and I am new to the game, so some of these may be hiding in there and I just haven't gotten there yet, but those are my suggestions for now. Sorry it was so long.
Happy New Year!
