@Koub
What a great suggestion to not mix items.. What if I want to build a factory that relies on belt-mixing techniques? I can think of plenty of situations where belt-mixing would be
extremely useful. There are ways to manage it with existing game mechanics, but it is very tricky and doesn't work with all belts.
Maybe you can suggest a game like Factorio which doesn't hinder me building great factories like I want to?
The whole splitter thing is so throroughly broken that you can't use them properly to balance more than two belts or do controlled injection of items to another belt. The ingame splitter mechanics are so that they will break nearly every mechanism you try to build with them. If you want to build complex things with it, the resulting "belt machines" will be broken by design and only work properly under certain conditions.
See this thread for example where they discuss 8-belt balancers and conclude that you even cannot balance 3 belts properly:
viewtopic.php?f=5&t=25008&start=30
As it turns out in recent threads, its also complicated and tedious to build a priority splitter (which would solve the merging problems partially) that works properly under all circumstances.
While I don't see the necessity for a filtering smart splitter, I would suggest at least a splitter where we can directly control via signals which inputs and outputs are active. A splitter where one could set priority for inputs/outputs would even be better.
And please don't repeat your arguments against smart splitters. I understand your points against it but I believe your arguments are short-sighted. Consider the fact that circuits in factorio have a very limited application.. people often complain that you cannot do anything useful with them.
Why is this the case?
Because you simply cannot control useful aspects of a factory. If you take a look at real automation, you will see that you need actors that are capable of tuning the parameters of your production flow. Where items go for example. In Factorio it is next to impossible to properly control where your items go if you want anything more complex than straight belt connections. Version 0.13 did make a big leap forward with wired belts but it is far from being useful. Another thing is that you cannot control your furnaces and your assemblers.
If you want circuits to be useful you need to make the game such that they can actually control things in a DETERMINISTIC way. Splitters for example while they are deterministic at a first glance don't really allow for deterministic item flow, even with lots of combinators.
I mean there are lots of engineers playing this game and you give them lots of cool stuff to tinker around with and in the end it turns out that this stuff is all so flawed that you cannot do great enigneering with it.
Maybe you can give it another thought and at least implement properly controllable mechanism to transfer items from one belt to two others.