On some cruise lines you can guarantee a minimum category - so on Princess you can book not just any balcony but a Cat BE (for example). That way you will not end up in a lower category and have that obstructed balcony. Certainly study your deck plan before booking a a guarantee. We did a BG guarantee on Ruby Princess because there are no obstructed balconies.
A Bad Day At Sea [with power] Always Beats A Good Day At Work
Carnival: Glory 2004, Destiny 2008, Splendor 2009, Freedom 2011, Valor 2012, Dream 2013
Celebrity: Summit 2011
Princess: Ruby 2010, 2014, Caribbean 2013, Coral 2014