Thermarest makes an ultralight inflatable pad, 3/4 length, orange on one side and black on the other. I'd argue the compass to stay -- I have used one a couple of times in unfamiliar cities and at rural junctions to orient myself. Down bags are the only efficient way to go in terms of heat for weight, in my opinion. I do most of my touring without a cell phone -- in many of the places I have been, reception has been scratchy, if it exists at all, and public telephones are still pretty reliable. It was pointless taking a cellphone to Europe last time I was there. But I *do* carry a PocketMail email device for use with public phones these days.
For anything over a week, I go with three pairs of bike shorts, three pairs of socks, and three jerseys -- and the destination will determine which two are long or short sleeved. I also take two polypro tops, leg warmers and tights (the latter can be used for added warmth at night) and several pairs of gloves. A long pair of microfibre trousers go in -- the zip-off convertible ones have become quite a bit cheaper these days. Microfibre is an excellent wind protector, and does pretty well on water repellancy, I have found.
All this, of course, is based on poor to moderately good weather. I also take a tent because I like to be comfortable when the weather turns bad and indoor accommodation is not an option. I don't like being annoyed by bugs and animals while trying to sleep, and a tent with floor and mesh walls, plus fly is a good investment over a simple tarp. I know Stokell loves his hammocks, too.
I have been down the lightweight touring track, and it has its interests in the challenge to minimise weight -- more so for the weight limits on aircraft nowadays. But I have found that every ounce, gram, pound or kilogram saved on a tour usually means a compromise on comfort, and I am old enough and wise enough now to know that the extra weight on the bike is almost heaven sent when I get comfortable in camp. I pack a Thermarest knockoff chair converter for the sleeping pad. I will take my thickest down bag if the temp looks like getting anywhere near zero, despite the extra weight and volume. I have a two-person tent for solo touring. I take a full-blown Trangia cookset with two pots, two burners and various other bits and pieces. And my clothing is like a wardrobe. I might need four panniers, but then the bike probably handles better, too.
By the way, you don't say what you are doing for food. Are you getting fixings each night for cold supper? Eating at restaurants? Living off the land?
I'd add in a spoon, too (nick it from McD or somewhere) because you *will* want to open a can from a supermarket and eat what's inside. I'd ditch the rain poncho if you're jacket is reasonably waterproof. The best quality ponchos are quite heavy, and the cheap ones don't hack it for mine on a bicycle. Use your tarp if you need to. What about a bike lock -- a simple cable lock will do. Lights? You don't think you'll ever need them, but you will one day on a two-month tour. Energiser, I think, makes a completely serviceable head torch that can serve as a headlight and for night movement around the campsite. On water filters -- I bought one five years ago, and have *never* used it on tours throughout Australia, northern Europe and England, and North America. Ditch it, and take some extra water bottles or bladders.
Oh yes, on the washing... nothing beats a good soap up in the shower or in a washing machine to get the skid marks out of shorts. Washing body or clothing in streams, especially with any soap, is not acceptable practice these days.