First. I love the game. It’s a lot of fun and that is what counts, however there are a few things that would improve it immensely.
Factions:
Factions are a great idea, but the way they are implemented is just not working. You need to seperate them completely in terms of items, gold, crafting mats AND STASH!
The only way these factions will ever work properly without tagging everything is by separating CoF and MG to different stashes. This way people can still switch if they want, but no items, gold or mats will ever be transferred between these two factions.
Right now switching factions with a char is a pain as it is. Most gear probably won’t be usable. All items aquired in CoF has a no trade tag which you can only by hovering over it (REALLY annoying) if you have a char in MG or switch over. People switching from MG to CoF for mats - resulting in nerfs - is not popular either, if you didnt already know 
MG:
The search filter is really in need of an overhaul. It’s no fun looking for stats on say a unique and having to go through 100 pages to find a high rolled one.
Getting favor by selling has led to everyone throwing their whole stash into the market at 0 Gold. That is hardly what you intended? Think this has to be rethought.
CoF:
My main complaint here is the lack of gold to buy stash tabs. It might not be an issue for “pros” running 1000 corruption, who know what to pick up (and especially what not to pick up), but for everyone else I feel like gold is of too short supply. Prophecies for gold or higher gold drops, thank you.
The grind to get to rank 10 is to much. I have a lvl 100+ and a 98 char in CoF and still only half way through rank 9. And yes I did spend all favor on prophecies. Again this was not a problem for people that quickly ventured into 1000 corruption with “broken” or overtuned skills, but for most others around let’s say 300 corruption it feels like too much of a grind.
General:
My main issue is the amount of broken skill nodes. There are so many that just dont work and many others are broken (resulting in overpowered / underpowered skills).
Let’s take the jelkhor trap thrower build as I have experience with that: Amazingly fun, but it’s obvious a couple of nodes are broken in the OP way. And yet there are also a few (on paper) powerful nodes that NO ONE takes in their build… because they clearly don’t work.
And that leads me to my second issue with LE:
All the outdated passives and skillstrees for a majority of classes. It’s especially annoying, when you can see every new class introduced having VASTLY superior passives and skills, while the old classes are left completely in the dust.
So yeah, I know it’s a work in progress, but this is where I hope you will dedicate most of your time. Updating passives and skills and fixing all the broken ones, while you do it 
Great game. I won’t be going back to PoE.