I don't know the play very well, but I think he hacked it down too much, because it just proceeded by a series of inexplicable but vivid events without any coherence. I have a feeling (guess) that Branagh felt that the play was basically a nonsense underpinned by poetry so he decided not to fight it, to make the plot even more ridiculous and surreal, but to support the emotional performances. I thought the acting was very good. Brian Blessed plays the good and evil brothers really well. Kevin Kline plays the melancholic Jaques with a gentle touch. Bryce Dallas Howard was good as Rosalind.
But for me, the lack of coherent structure spoils a film or play. I like a sparser chillier style with an implacable logic more than a lush emotional set of scenes without structure. But it wasn't poor, it just wasn't quite what I like best. I still admire Branagh for his vitality in giving Shakespeare to us in lots of different ways.