A few suggestions

[Mysteria9]

Here are a few things I'd like to see:
•1 - Craftable floating platforms. These can be placed on water, and then other things can be placed on top of them. Perhaps only "small" things like belts, inserters, poles, and pipes?
•2 - Craftable backpack. This would increase inventory space and is placed in the armor slot. A fair trade-off in my opinion!
•3 - Green wires should be a brighter green, they can be quite hard to spot sometimes. Have a look at this picture: (there are 9 green wires)

•4 - Free wire condition. On the smart inserter, where we drag the slider and select an integer for the condition. It would be very nice if we could click the number and enter our own value.
•5 - Would be nice if we would get our red/green wires back when we mine the thing they are attached to.

Enough writing, I have a factory to build!

[EditorRUS]

In order:
1. I don't know situations, where it could be used. However, that game very needed a boats.
2. That's insane. Probably, you want take your whole factory, and move it to other place? It only thing where your idea useful. But... if multiplayer will be implemented then idea could be useful. Not now.
3. Okay, that's graphical problem.
4. Okay.
5. Okay.

[Candunc]

Replace 1 with bridge, made out of wood?

That way you can walk, place conveyor belts, wooden chests on it, but limited to items that seem 'light'

Iron bridges could hold everything else including railroad tracks.

[MF-]

I fully support 3,4,5
And bridges.

I probably woudn't have an use for a backpack.
Although.. In my recent freeplay map I had to go quite far from the starting point (which had plenty of coal, iron and copper) to get some stone.
Having a possibility to transport way more in one go would be nice.
But I expect to have some sort of fast transport ready when I ran out of the first stone batch.

[orbito]

Good suggestions.

I'd also like to see more stuff to do with water. Being able to build bridges would be useful.

[ssilk]

Necroing this.

1: Suggested several times. See "bridges".
2: Is implemented as modular armour. Inventory size can be modded.
3: Graphical issue. Meanwhile much better, steady improvement.
4: Comes with 0.9.
5: Would be much nicer, if no wires needed at all, cause it has no game-value to produce wires for the connection only. Wires could be "inside" of the poles.