There is a current rating system? What is it, reading the logs?
The number one thing to fix the problem is to allow more filter fields in the search. There are plenty of attributes that are attached to a cache, why can't I filter on those? Show me all caches in this area with "significant hike" and "scenic view" attributes. Is that a premium option? If it is, maybe that should be made more clear and I'll upgrade right now.
I live in Western Mass. I naturally want to snag all the local caches I can. Even the cheesy park and grab (great for rainy days). But if I get a week off of work, I can go into the New Hampshire mountains. Read the logs? How many caches do you suspect are in all of New Hampshire. What if I just want to go somewhere in New England? Reading the log files only works if I have a specific destination in mind. I'd like to pick my destination because of the cache, NOT pick the cache because of the destination. In fact I'm only guessing at the mountains because I -think- there are going to be great caches there. What if there are a bunch of highly rated caches in the city?
I'm not so interested so much in an actual rating system, but anything that will separate the ten minute parking lot cache from the epic hiking caches.
And to respond to "...just too lazy to read the log entries", I'm not going to read through 150 caches' log entries. I might get a half hour to an hour of computer time after taking care of children, putting them to bed, bills, cleaning and so on. I read what I can, but just because I don't read them all, does not mean that I am lazy. Having some way to get recommendations, ratings, favorites, whatever helps get me off the computer faster, and into the woods.
Hate to compare to site like slashdot, but as far as ratings, it doesn't have to be just 1-5 stars. Slashdot also has categories like "Informative" and "Funny". So that really neato kayak cache might be "+5 Unique". It's been said that ratings will only hurt geocaching. I tend to stay in the traditional caches, however I think there is also a chance people would break from their normal mode to check out that "+5 Puzzler" to see what all the fuss is about.
Anyway, to sum it up. I'd like to plan geocaching getaways and vacations. I'd like to pick the destination based on the caches. I've only been able to search for caches based on location. I might get lucky searching for keyword, but good luck. I'd really like to just pull up a map of New England, then start filtering out the caches based on the attributes. Then head off to the area with the most dense cluster. Three day weekend, here I come.