There are many items that feel as though they are in the tech tree in the complete wrong order: many many buildings that require electricity to function and you don't get power until WAY down in the chain.

Also, I feel like all logistics items, like undergrounds, splitters, long-handed inserters, etc. are so annoyingly far down the tree that it makes things very tedious and unfun to play. It's just irritating, annoying, and feels like you are punishing the player, rather than allowing them to work at their best, especially within a modpack that is already very complicated. I would highly suggest you put those items at the top of the tree where they belong to allow the player to use them asap. >Radars should also be usable from the first minute of gameplay, since there are so many ores, and it takes a long time to find them by foot.

Also, my antimony is super far away, but there are no trains in sight... another item that should be moved up.

I had the same feeling about electricity, but finally found out that there is a burner generator unlocked by electromagnetism

See above for electricity, but yes splitters and long inserters are a bit later than vanilla, I didn't think of it as a problem, but I might move them up if that's a big worry or "unfunny" factor.

along the lines of this I feel like an early game splitter should be available as a counterpart to the mechanical inserter, without the filter component of course. this and something similar to a long inserter would go a long way towards making the early game progression less of an undiplomatic punch in the gut, and more of an introduction to the challenges of managing byproducts.
at the very least I feel the techs that are purely one building with no usable recipes, or for a process that you cant access should be reevaluated.
I'm all for the silly labyrinthine tech tree, and byproducts that take a while to become useful, but things like chemistry 1 and 2. Should at least have a low efficiency recipe.
I need to compose my thoughts more thoroughly as I work through the pack, but this is an early snippet.