In short, overall, I was satisfied, but there are some questions. I'll try to elaborate on each mission.
Mission 3
1) I got lucky at the start; they gave me a Warlock. Since there's a time limit and you need to take it, I decided why not, and I managed to complete it on the first try, even though I initially thought I'd have to replay it.
2) The quest with the nymphs and fairies was cleverly designed. I initially approached them all, and they just laughed, but it turned out to be simpler than I thought, and I didn't need to approach any of them; everything just happened on its own.
3) I didn't complete the clover quest, probably like most players, because there were too many losses.
4) Overall, I had time to explore everywhere, thanks to the logistics. In the end, I ended up with a Chaos Mage, a Light creature (they gave it in a hut; I thought, why not?), a Warlock, a Charon, and an Imp. I defeated the bandit, the Ents that give a lot of experience later, and the Silvan Elder, and the final Ents... I'll post screenshots of the battles.
Mission 4
1) I completed it on the first try, but I had some questions about breaking through the fort on the hill. Fortunately, there's a Berserker nearby, and I used him to break through the mine to get rid of some units and then headed for the Wizard's Guild and the Berserker.
2) The key guardian was a bit annoying. As soon as you enter the hut to activate the attack on them and the mines, I didn't understand why it wasn't possible, but in the end, it all made sense.
3) I lost most of my mage army, but it's not a big deal; there's an Elven Castle where I can replenish my forces...
Mission 5
1) I really enjoyed this one. The only thing missing, in my opinion, was a mentor, and there were very few artifacts.
2) I protected my army like the apple of my eye, and I don't think I lost anyone, but what's the point if they take it away from me at the end?...
3) If you don't want to bother, stay with the Dark Elf, and everything will be fine. But if you want to challenge yourself, you'll have to fight the Elf, and there are some questions about how to kill this overpowered enemy that you raised yourself... but I managed to defeat him after the third or fourth attempt. You need to take the Armor of the Forgotten Hero from him because there was a situation where the Ents standing randomly near the Unicorns simply resisted three Earth Shocks in a row.
4) What's the purpose of the Mage City? They could at least add some kind of artifact shop there.
5) Bonus: If you're bored and want some fun, you can kill 24,000 Cyclops, which is what I did. If you're interested, I'll attach the replay.
And yes, playing with an Elven army and a Mage is more fun than with my own, maybe because I played through the Light faction. Overall, it's a great campaign; respect to the creators!