I am now finishing my second game, and here are my thoughts: 

1) Regular units are quite useless. 

When I played the first game I was trying to play it the way I played FE. It was mistake. In my second game on hardest difficulty, which I am about to finish, I stopped training regular units altogether. So far I have trained one scout, and lots of pioneers. The heroes are so strong and self-sufficient there is no need for an army - especially once they gain 2-3 levels. I have still gained number of units from neutral factions and quests, but they are just stationed in cities. Heroes move so fast and clean map so well my cities do not even get attacked. I think the situations will get even worse once unrest is introduced - I need encouragement to train troops, not the deterrent.  

2) Tactical battles are boring. 

FE had a good balance. On one hand, there was this empire building task, with lots of buildings, economy etc. On the other hand, you had also epic battles including your experienced and upgraded and cherished units. In SK there is only one way to win and thus the game acquires strong militaristic focus. My feeling was that therefore the battles should be more epic than in FE. It does not happen b/c battles are generally too fast which causes couple of problems: 

• units are too close - and the initial placing of units become extremely important. I had battles that turn from very easy (no casualties) to very hard (3-4 casualties) just depending on the starting position. 
• battles are so fast there is no time to use all this fancy skills. Hero can have like 10 usable skills, but I know I will at best use 1 or 2 of them. Thus, all the battles seems to be the same, and they have mechanical taste to it. 
• and then AI that has not been updated for a long time makes battles predictable (though here I have to admit that some new AI skills - bashing, switching positions - which disrupt my positions bring fun to the battle)

3) Magic is useless.

The only sov available right now is a wizard. This makes me worry because I should be playing with the heavy focus on magic, but I do not. Of course, once the summons are added, and we have more spells, purely magical approach would be probably plausible, but for now there are some serious problems which make me think already: 

• mana - mana is purely related to shards. Since the premise of the game is that I desperately try to protect shards from attacks of overwhelming enemy it stands to reason that shards own by player should be few and between. Or from other perspective - if I own majority of shards, or big number of them, it means I am already winning decisively and I do not need magic. In other words, if my strategy is based on magic I need a lot of mana. I need mana for a research, I need mana to unlock more spells per battle for my sov, and finally I need lots of mana to cast those spells. If right now I have to fight multiple battles per turn, I would need a really good mana income to sustain my expenses. Apart from that, by casting spells I also decide not to boost my empire by summoning building/units. The solution can be to add buildings that provide mana, or new heroes skills, or sovs skills. 
• if game has such powerful meele heroes then there is no real need to use spells (nor summons). This can be changed, if more challenging enemies are added.
• if battles are taking place so fast, again, no time to cast spells 
• and then mana is also a currency