suPHP does have some features that I do like over phpSuExec. However, you also need to do a lot of patching and fixing of the suPHP code to really get it to work. I am testing a suPHP set up on one of our newer servers to see if there are any issues. The main feature in suPHP that I really like is the ability to add a suPHP_ConfigPath to a VirtualHost entry in the httpd.conf file. This means that you as a server administrator can control custom php.ini directives per account. The phpSuExec solution is to read the php.ini file that is in the same directory as the PHP script. This can be a hassle if you have one account that wants to have register_globals enabled on their account, but you do not want to enable it server-wide. With phpSuExec, you have to include a customized php.ini file that has register_globals enabled and place that file in every directory on the account. With suPHP, you simply create one instance of the modified php.ini file and then use a suPHP_ConfigPath directive in the httpd.conf file and then all requests for that VirtualHost use that customized php.ini file.
However, the main issue involving using suPHP is the fact that you have to include the suPHP_UserGroup directive for each VirtualHost. You can accomplish this by editing the default VirtualHost template, but this will be overwritten whenever you update CPanel. Ultimately I think there needs to be some degree of allowing a customizable VirtualHost template, so that suPHP will automatically work on new accounts.
There is a Bugzilla enhancement request for this (Customizable VirtualHost Templates) at:
Unless the CPanel developers want to incorporate some of suPHP functionality into phpSuExec, then I would think that allowing Customizable VirtualHost Templates would be the first step needed to really start any type of community involvement with CPanel and suPHP.