Well you can't decide which is a bad site and which is a good site...people are building a website to earn some money and they may well put a lot of effort to maintain it...even if they don't it really doesn't mean that a particular website is a "bad" website...well the thing google will look upon is that
1. you don't have more than 100 links per page...well I prefer not more than 40 links per page...looks decent

and 2. it's so obvious...if you have too many links then definitely the link juice be given out..
the 3rd question is not that clear..but to the extent i understand...the newer links would be put in front and the older links be shifted to next page...hence the PR values to the older sites would decrease...as the new page won't have the PR...but it is temporary...after some time the inner pages would also get the PR...and then again making the problem solved...
Take care
Manish