In reply to Jonny2vests:
I think you are almost certainly right and I must get around to rewatching it.
It did have problems though. General Grievous was a huge let-down after all the hype (and his terrifying build-up and introduction in the 2D Clone Wars series, but I suppose we should let the feature film prequel trilogy stand alone). His demise was so lame that I thought "oh, he's bound to come back from that" and was disappointed when that was it (just a single blaster shot from Obi-Wan).
Christensen (or rather, his dialogue) let things down again, with the "younglings slaughter" and so on. The shoehorned-in rushed appearance of a load of peripheral Jedi (and of the Wookie planet) felt, erm, shoehorned-in and rushed.
The final fight between Anakin and Obi-Wan, although very well realised and choreographed, was rather too grisly - I mean, I liked it, but it didn't fit in with the rest of the family-friendly vibe of the films. The lingering shot of Anakin's near-dead, dismembered, charred twitching form, was a bit gratuitous. But you are right, the incredibly bleak ending is totally forgotten/overlooked by everyone and arguably far outdoes the ending of TESB!