It is due to the asynchronous way signals are triggered at the level of C code. Signals have to be delivered synchronously with respect Perl op code dispatching. Every agrees there needs to be one event loop for all of Perl. I propose that it be in the Perl core as it needs to be able to interact tightly with the other control areas. Timers Perl needs the ability to support multiple timers.
Timers can be independent or associated with an events.
This list meant to be a catchall for all logic flow related issues. This is a major subset of all language issues and would focus energy on these topics. It would also lower the volume of the parent language list. Doing all of those things correctly and elegantly is not trivial. I see the need to solve them all together as we don't want multiple comflicting paradigms like Perl5 currently has.