Minecraft 1.9 is on the verge of being released (at least I hope so, how long can it take them?!), and during the wait there's been a lot of debate about the "Combat Update". Some people love it, others hate it. I won't give my opinion on that. What I will remark on, however, is the following:
In this update, we're a getting an expanded End dimension, a new combat system, subtitles, new enchantments, and wings, because why not?! A whole lot of thought and work went into these new features, I'm sure, but there's a common theme: they're all so, well, new. Mojang isn't really stretching the current features with this update. They're throwing in all these new game mechanics that were not necessarily needed. Instead of building on the core features, they're adding all these new ones that don't completely fit in with the old ones. I don't think this should be avoided. Rather, I think that Mojang is avoiding adding simple things that could really improve the game without being new and flashy. And so, I have compiled a list of those things that have been needed for quite a while!
Obviously, these are just my personal opinions. If anyone reading this thinks of an idea, post it in the comments! If it fits, I'll add into the list and credit you for the suggestion with a profile link. Anyways, on with the list!

Text
Books
*credit to my friend biosoldier1 (not on PMC) for inspiration

Anyone who has ever written a book in Minecraft knows that the system is, well, just plain bad. All you can do is type characters, hit space or enter, backspace, and click next. To correct an error, you have to backspace aaaalllll the way back to the word instead of just clicking or hitting arrows to place the cursor right behind the word. So what if books were like text editors? Mojang doesn't have to make Microsoft Word or something. They just need to add more intuitive mechanics to the system. But it would be nice to highlight text and edit large sections of the book, or maybe center it?
It would be incredibly convenient as well if the last page you were on was recorded when you closed a book. That way, you don't have to click the next arrow all the way to where you last were. Instead, opening the book again takes you straight back to that page.
Also (credit to EliteCrafters3009 for letting me know that color codes can be used in survival with books), it would be good if using color codes in books was easier, requiring just the '&' symbol and the character assigned to that color following it like normal. This would be a lot better than having to look up the '§' symbol and pasting it in. With that in mind, on to the next topic!

Color

Color codes are great and all, but not counting the effects like underline or italic, there's only sixteen of them. On the minimal level, wouldn't it be nice to have access to an extended palate like the one below? It really doesn't seem that hard to do, and it'd give us all a ton of new colors to use in custom messages!


Going broader, what if we had access to the whole RGB values system and perhaps even font sizes? This would be a little more difficult and couldn't really be said to be necessary, but it'd still be awesome! But let's go broader: what about highlighted text with the same range of color? Or changing the color of an underline? Okay, this is getting out of hand. My point is, there are so many possibilities for giving players more liberties with text. Sometimes it's a little nice being restricted since it prompts creative manipulation of limits, but ultimately it just restrains possibilities.

Chat Messages

Ever wanted to post a long paragraph in chat, but you had to send it one sentence at a time? The limit on chat message length can get really annoying, especially with pasting in text like links. So here's an idea: unlimited chat message length! But there's more to this. If it were seriously unlimited, that could cause spamming problems on servers. So how about a chat message length gamerule? With this idea, you would be able to use '/gamerule messageLength' set how long you would like chat messages to be limited to in a world. The default could be the normal length, but could be set to unlimited using the value '-1'. Otherwise, chat messages will be limited to the length set by the command! This could have a lot of cool uses such as limiting messages to 5 characters for a special minigame.

Crafting Guide

At this point, anyone starting to play Minecraft had either watched enough let's play videos to know crafting recipes or knows about the information held on the Minecraft wiki. But isn't it kind of ridiculous that you actually have to look up stuff on the internet to progress in the game? Some recipes are intuitive, but some are just plain hard to remember. So here's my idea:

There should be a crafting guide! A great way to do this would be to model it after the achievements system. You're provided with the basic survival recipes at the start of the game. Then, as you use those recipes, you unlock other recipes, which once used unlock others, and so on. This would make progression in the game a lot more understandable and fun, and then, when you're struggling to remember the crafting recipe for a lead like everyone does, you can just pull up the crafting guide! Thus, this addition would benefit both new players and seasoned ones.

Textures
The default textures are generally pretty good, but some are just not that great.
These comments explain it all:

So yeah, some default textures reeeaaalllly need to be redone.

Blocks
There's so much possibility in this category. The designs players can create are limited to the few block types and orientations available to us. People have figured plenty of clever ways to make something look like they want it to, but there's quite a lot of extra blocks that could be added to expand the builder's inventory.

Stairs and Slabs
There really needs to be stair and slab versions of these blocks:



Walls
Wall/fence versions of these please:



Also, it would be very nice if wooden fences and fence gates connected to cobblestone walls, as currently, they do not:



Bricks
And while we're at it, why not brick versions of these blocks?


By bricks, I mean that they should have the same texture as the above blocks with the stone brick crevices pattern overlaid on top.

Also, what about different colors for brick blocks?
Credit to MonorailblueS

"Here's an idea that i've had ever since 1.6
came out: Stained clay bricks. Normal bricks look reeaaaally ugly to me,
and are limited in what they can be build with. If they could be
combined with stained clay to have different colors, I think that would
add a bit more diversity to building with bricks. ;)"

They'd basically have the same texture as normal bricks, but have the shading of their stained clay counterparts. Also, for aesthetic reasons, the white mortar between the bricks would be stained as well. I'm thinking that the crafting recipe could either be like stone bricks with 4 stained clay in a square, or 4 stained bricks in the same pattern. Either way, this really needs to be added!

Ceiling Player Heads
Player heads can be placed on top and on sides of blocks, but they currently cannot be placed so that that they appear attached to the block above them. Thus, I think this should be a mechanic! It'd be quite nice to have mini wood log blocks attached to the ceiling using the "MHF_OakLog" head; ceiling heads would be an invaluable asset to builders.

Sideways Stairs
By sideways stairs, I mean this:


(Drawing skills on point)
Stairs can be placed upside-down, which is amazing, but imagine the possibilities if they could be turned on their sides!
This would of course take a weird clicking pattern, but I think it's perfectly possible.

And last but not least...
The amazing,
game-changing...

Vertical.
Frickin'.
Slabs.


'Nuff said.

(Once again, sorry for the poor visuals :p)

Thanks for reading, and don't hesitate to put your suggestions in the comments!