This is what Minecraft 2.0 should be like in my opinion. As far as mobs and animals go, anything goes, these are just my ideas.
Items, Blocks, and Ore
First of all, no more diamond armor. It dosesn't make any sense. Diamond tools are still good though.
Titanium would be a new ore. Titanium dust would be found by mining sand with a shovel enchanted with silk touch. Then you could use an electric furnace to turn it into titanium nuggets, and then titanium ingots.
These would be pieces of diamond that are the equivalent of nuggets of other ores, but with the disadvantage of the fact that they couldn't be reforged back into diamonds. They are only useful for currency and making diamond arrows.
Iron nuggets were added in 1.11.1, so this will not release in 2.0 Update. More about 1.11.1:
New arrows would include-
Diamond arrows, which deal 12.5 damage as opposed to the normal arrows which deal 9. It would be made by replacing the flint in the arrow recipe with a diamond shard.
Stone arrows, which deal 6 damage and would be made by replacing the flint in the arrow recipe with a piece of cobblestone.
Iron arrows, which deal 10 damage and would be made with an iron nugget.
Gold arrows, which deal 9.5 damage and would be made with a gold nugget.
Bomb arrows, which deal 8 more damage then the arrow you make them out of and explode with about two-thirds the power of a creeper explosion. They would be made by combining any other arrow type with two gunpowder.
Flame arrows would deal 9 damage, ignite the target, and actually ignite any blocks they hit. They are made by adding one piece of coal to any arrow.
Flare arrows deal only 5 damage but light up the area where they land and have a 40 % chance to ignite mobs they hit directly. They are made by replacing the flint in an arrow with a torch.
Scatter arrow. A scatter arrow expands into 3 to 6 normal arrows that each deal 8 damage upon firing, depending on how many arrows you used in the recipe. The recipe is anywhere from 3 to 6 normal arrows and 3 string.
Potion arrows. These are arrows that are made by mixing an arrow with the ingredients to any type of potion. The ones that deliver negative effects deal 9 damage, and the ones that deliver positive effects deal none.
This version of the furnace is made by 4 iron blocks and 4 iron ingots. It can only be powered by coal, oil, or at least 4 daylight sensors, and absolutely devours coal if that is what you decide to use. The electric furnace is used to refine titanium and aluminum, or to electroplate gold onto any object, turning it into a golden version of that object.
Ruby, Saphire, and Emerald tools
Rubies, sapphires, and emeralds can be made into tools. They are all equally rare and are completely interchangeable in villager trades.