Pitches are rated for 140-160mm forks, and, being a Specialized, are long and low to the ground. This is why people like to size down a bit. That said, I'm 5'8" and find my medium spot on. The wheelbase is long but the cockpit area is surprisingly short in comparison, IMO. I tried a shorter stem but didn't like it. They do benefit from some wider bars though.
I've just switched my (09 model) coil Pikes for coil Lyriks, and it's just like the same bike but, MORE, if you know what I mean. We went riding in the Dales last weekend and I did some pretty big climbs and descents on it, and it was perfect. I can wind the forks down for climbing but even when I didn't it was OK really.
The 09 Pitches came with rather weedy DT rims (Same width as a 717) but the '10 models have beefier wheels, which will suit the bike a lot more IMO. I've built some Sun SOS rims onto Hope hubs (36 spoke, plain gauge rear wheel) changed the bars, saddle, brakes (Magura Louise) fitted double and bash and usually use flat pedals which suit the bike more IMO. The Lyriks are superb, and I'd say a longer fork of any make would be a great upgrade. 🙂