Bittersweetness

I recently finished reading Maggie Furey's Shadowleague trilogy.  In short, it's good - pacey and gripping, with a range of interesting characters and situations and some unique features to the fantasy-world setting.  I am very pleased to have read it.
ALERT: SPOILERS FOLLOW.
One (of few) complaints, however: the ending was too happy.  In the last few chapters of the third book, several characters seemed about to die.  While difficult to read the deaths of characters I had come to care about, it seemed appropriate that the conclusion of the story should not be without real loss.  However, these characters that had been about to die, all recovered in a series of minor dei ex machina.  Glossing over the problem of dei ex machina, my specific problem at the end of the Shadowleague is that not enough people died.  It was not bittersweet enough.  Victory was achieved...but at no cost.
I have a continual problem with unconvincingly happy endings.  Bittersweet endings are so much more poignant and satisfying.  This is the biggest problem I have with the Harry Potter series - not bittersweet enough.  Also one of the best things about LOTR - beautifully bittersweet.
The Shadowleague is a good series and I recommend it.  But it suffers in the same way as many other stories - it lacks the bittersweet ending.