What are the technical reasons that Magic Quotes has been removed from PHP 5.4 ?
From PHP docs
Performance
Performance Because not every piece of escaped data is inserted into a database, there is a performance loss for escaping all this data. Simply calling on the escaping functions (like addslashes()) at runtime is more efficient. Although php.ini-development enables these directives by default, php.ini-production disables it. This recommendation is mainly due to performance reasons.
Is there any other reason why Magic Quotes has been removed from PHP?
this is very well explained why the deprecated in manual by chao
also good read Wikipedia : Magic quotes Criticism