Too slow - I'm actually totally ok with generalizing early, specializing later, but it's still too slow currently. I've finished multiple games without reaching the end of any of the three trees.

Just fine. The AI isn't competitive enough to really cause me to reach the end of the tech tree. It will be nice when we get it competitive enough to make the end of the tech tree more viable, but I don't have a problem with the pacing. It could be sped up a little bit, but it is fairly close to optimal so that it would be easy to make it too fast.

I third that. As far as I can tell the tech trees and the bonus they provide are decent enough (even if balancing is still a big issue, especially considering the overpowered champions), the only gripes I have with researching is the speed. Even if you set the research rate to fast it is way too slow after the first three or four tiers of techs.

Hard to comment on until there are some fixes to the rest of the game. Currently the Civics Tree does not change tech speed enough IMO. It would be much nicer to see research bonuses applied the same way attack and defense is set up. 

A University for Civics Tree, a War College for Warfare Tree, and a Conservatory for Magic Tree. If there were research buildings that gave you percent bonuses to all forms but more in one area, it would make things more interesting. Right now researching all the way up the research tree takes longer than just going after the techs you want. 

I already started a thread on this topic a few days ago, but since this the active one, I'll chime in and say that I feel the tech tree is far too slow and I wish the option to speed it up was much, much faster.

It's a little on the slow side.  Though I think that's mostly because there are too many techs that don't do all that much.  In terms of gameplay, the time between new techs is pretty decent.  You have to play the game with the techs you have access to, not just wait for your research to quickly steam through a bunch of techs so you can do awesome-thing-B.

The problem, though is that I wait through dozens of turns to get... drum roll please... warg riding... woop de doo.  This is just a redux of the too many buildings problem.

My idea is to divide techs into branches and leaves.  Branches would be integral techs that cost a lot to research and make a big difference in the game.  Leaves are support techs (like warg riding) that offer distinct advantages/weapons that you can either research normally or buy using gold/mana.

Agreed. Some of the per-requisites seem non-associated. I really like the branches and leaves idea. It would seem to provide some advantages to just getting a tech versus really investing in it. Unlocking a branch could then allow you to choose which leaf you wanted to invest in, whereas now you just get all or nothing with each tech.

I also dislike how currently Exploration falls under the Magic category. It doesn't fit well under any of the others, either, so I suppose that's the best spot for it.