Not sure of what kind of legacy features you would want to be removed but it's not like they are just building on top without thinking.
PHP 5.4 will also drop:
- safe mode
- register_globals
- allow_call_time_pass_reference/y2k_compliance and other legacy ini stuff
- "continue 123" syntax (can be replaced with goto). As far as I recall this is done since it's barely used and if removed would allow to implement some opcode performance optimizations.
Dropping some PHP 4 era syntax is obviously out of question due to already mentioned webhosting and backwards compatibility issues.
PHP 5.4 will also drop:
- safe mode
- register_globals
- allow_call_time_pass_reference/y2k_compliance and other legacy ini stuff
- "continue 123" syntax (can be replaced with goto). As far as I recall this is done since it's barely used and if removed would allow to implement some opcode performance optimizations.
Dropping some PHP 4 era syntax is obviously out of question due to already mentioned webhosting and backwards compatibility issues.