Gentoo is removing Adobe Acrobat Reader because Adobe hasn't updated its Linux acroread program in years and there are security issues. 

That said, Acroread has some nifty printing features lacking in okular.

Acroread has these missing features:

Current View
Page Scaling Options {None, Fit, Shrink, Multiple, Booklet}
Autorotate
Choose paper source by size (with suboption to use custom size when needed).


Current View + Fit to Page is useful for when you want to enlarge and print just a region of a page. Or if you just want to enlarge a scan e.g. of a driver's license. 

Choose paper source by size is useful for when a document is composed of e.g. letter and legal sized pages (very typical in legal/banking fields), where it's very convenient to click print and have the printer grab letter or legal paper from the appropriate tray as necessary. Often times there are legal standards regarding formatting (margins, print sizes, etc) whereby documents must be printed on the correct size paper without enlarging or reducing to fit (or worse, cutting off the top or bottom of a page). 

Autorotate is convenient, too, as often times people scan documents on lengthwise to speed up the scanning process. When printing, though, it's convenient to print rotated correctly so that the page isn't shrunk down or cut off.