Not a good idea.
You wouldn't believe how many people use plaintext passwords in command invocations (wget http://username:password@somesupersecretsite ? lftp ftp://username:firstname.lastname@example.org ? mysql -u admin -p yeahthisissecret ?). Sure it's their own fault, but a simple ps faxuwww or top (or even an automated script doing that) can easily net you lots of passwords from "your neighbours".
My server didn't have grsec enabled for a while. It was indeed nice to see some of the royal a**holes driving the load up to 20 or more (yes buddy, it's a splendid idea to run 20 high I/O and high CPU processes at once) and get some insight into what services run on a single server, but the potential for abuse is definitely there.
You can of course see home directories. Some people even get their permissions wrong and you can descend into their homes. (it might be a good idea to set the permissions of /home from rwxrwsr-x to rwxrws--x to reduce the amount of information you can glean from there, though I suppose /etc/passwd is even more of an information-well).
And for yourself, if you do not run any websites on a particular account, there is absolutely no reason to have permissons of 755 or 751 on your homedirectory. 750 is perfectly fine (if you want other accounts within your group to have access), or even 700. Even if you do run a website, all that is STRICTLY needed is 001, though most people would do well with 701 instead (never remove your own access unless you absolutely know what you are doing).
And one last thing; Privacy is important. There is no reason you should be able to "monitor" exactly what I do. Maybe what I do violates some code of ethics you have (there are pr0n-sites on DH, after all) and you'll come up with some excuse to bash my account to support. The less you know about my account and I know about yours, the better -- not only for me, but for you as well. If your account gets compromised, at least the attacker can't see what fastcgi apps I am running, what paths I am using, and other "interesting" things that might make it easier for them to compromise my account, as well (it's infinitely easier to compromise more stuff once you have a foothold on a server, i.e. once one account has been exposed; and really, do YOU trust all the silly passwords people set for their accounts ?)