Inspired by a similar post, I came up with this idea and didn't want it to be hidden in a comment and not really seen by anyone. I have the idea for a splitter than works very similarly to the normal splitter in that you cannot filter items coming through it, but you can set how many items it outputs from each exit per cycle. As an example, if you want to do a 1 to 5 split currently you have to make a really convoluted mass of spaghetti with a bunch regular Splitters to do it. With this Adjustable Splitter, you could set the outputs to Left 2, Center 1, Right 2 and get a 1 to 5 split very easily and neatly. With a total of 5 (2, 1, 2), that means for every 5 items that pass through the Adjustable Splitter, 2 go left, 1 goes center, and 2 go right. This would allow you to make a 1 to 5 split with only 3 Splitters, one of which being the Adjustable Splitter. I made a crude drawing in paint to help illustrate. https://imgur.com/a/u7qdIvh
This Adjustable Splitter could be a Tier 3 item, since regular Splitters are Tier 1 and Smart Splitters are Tier 5, it would make sense to pit this right in the middle at Tier 3.