Finally completed the main (i mean the one that was in game since nearly the beginning of development, with the Wesnoth kingdom "heir" ) campaign last mission. It was a nice conclusion with a big brawl that the attrition factor favoured me as at some point the enemy commanders weren't able to keep up
with their gold sources captured)
It's been years i have been playing it, then roughly each time reaching mid-story dropped the game, and tried again months later with each new Wesnoth version.
But this time ( 1.9.x ) i finally kept at it, and managed to get through the whole campaign.
The only real annoyance i had and always have with that game is how luck dependant it can be. In fact it reminds me of one of the main annoyance i had with the early Civilization game, i mean the "medieval pikeman that kills your modern battle tank" despite the numbers tells you it should not be possible.
That lead into so much of your troops that you managed to level up during several missions (though unfortunately most of them do not level up more than level 3, each new levelup gives only a very few more health points) to be killed in a turn.
At some point it's just annoying, and that was why i usually stopped playing.
But the devs are aware of this being an annoyance to some players and they made it very easy to replay a turn, as it's available in the menu without having to load a game.
This feature actually helped a lot me to not reach the "oh now that's annoying, let's play something else" status.
This problem does not exist strangely in skirmish, as i played a few of them on some maps against the AI, maybe it's because you don't get the troops to survive long enough to become high level and so do not attach yourself to them.
Some missions have been very challenging, some more straight forward (the river crossing , i don't think it gave any kind of difficulty), but despite a few that felt repetitive it was overall an interesting campaign, the scenario with the 2 big army clashing while you were trying to move through was rather original, as you had to sacrifice the elf helpers troops to distract enough of the enemy legions and rush into the hole of the battlefield.