Personally no issues with the download...added the key to steam like normal and started straight away.
Have played for just over an hour now, I never put huge amounts of time into FE or Legendary Heroes so bear in mind I am coming to this rather fresh. Just a few initial thoughts:
- The maps seem really big, it is perhaps just deceptive or the other games may have had maps this size but for 'small' maps they seem rather large to me 
- There seems to be a lot of (as the walktrhough PDF puts it) 'crud' on the map....lots of unfriendly encampments and units pretty close to my starter city. You start of pretty weak but the the ramp up in power seems fairly quick early on.
- Some of the in progress quest text is very amusing, I am specifically talking about the minor factions blaming stardock for not being included in the beta 
- Crafting seems very useful...making mana potions early game to rush out some units seems rather important in my game so far. Overall with the doom timer and the shards being attacked the game feels like it has a fair bit of pace to it early one....pretty different to how a lot of these games work.
- Game looks very nice and is running very well, no crashes or technical issues so far for myself.
One of the few problems I have noticed so far is that some of the UI elements/text seem very small, the unit icons on the bottom left of the UI when garrisoned in a city or outpost come to mind the most, maybe I am missing an option to scale the UI?
I also activated an ability on the the tactical map while a unit was moving...I expected it to queue (and be performed after the unit had fully moved) but the unit stopped and performed the action straight away, maybe it has always been like this in these games though and I shouldn't be rushing haha.
Very much enjoyed what I have played so far overall, very promising start.
