I think maybe a better design would be a gusseted pocket with a drain at the bottom. But that would cost more, get in the way more and not look so neat. Not looking so neat shouldn't really come in to it for a technical climbing jacket, but let us not kid ourselves that sales overall would probably suffer and at the end of the day business has to make money.
You could also use something like the RiRi Aquazip, and some jackets are starting to use these on pockets as well as main zips. That's a better solution too, IMHO, but again will up the price and would make the jacket a little less flexible in use. I'd still like a drain though. On a climbing jacket the big pockets are there on the front so you can easily access stuff you need while you might not easily get to your pack, or just put things down. That ease of access does make them vulnerable to water getting in.
So, back to the issue at hand... If you want stuff dry then a jacket pocket and nothing else is The Wrong Answer, as Martin points out. So you don't stuff a glove in and have it come out sopping wet, a periodic emptying stop might be a good idea. If you think that's less than ideal I'd agree, but the jacket is to keep you dry, not what you put in the pockets.
For long walks in continuous heavy rain you'd probably be better off in a longer cut jacket where the pockets have entrances behind stormflaps. Do a technical winter climb in one of those and try and get the ice screw you just stuffed in a pocket out quickly while holding on to an axe with one hand and you might find everything's a bit more awkward than you wanted... If you must carry a 'phone or ipod etc. on your person then use an inside pocket.
Pete.
