missing E_NOTICE support
I know that many PHP coders just like PHP because it's quick and you can be lazy. That's ok!
Correct me if I'm wrong but when hacking the startup/debug_logging .php to run the whole framework with E_NOTICE enabled, i got 1000+ notices just from C5...
In my opinion a professional framework like C5 should support various programming styles and even though many PHP coders don't see the advantages of E_NOTICE on and rather suffer from dumb errors in their code producing bugs they could have noticed right away, I think E_NOTICE is a good thing, easy to circumvent in your own code (@) and still not very hard to circumvent in 3rd party libraries (call-wrapper which changes the error-level before and after the call).
Any thoughts on why C5 doesn't support this or whether there are plans to support it in future releases?
I do believe this issue is a large contributor to the slower speed and memory usage of c5. You might agree if you have time to watch:
Rasmus Lerdorf - State of PHP 2012 (~ 2 hours)
Unfortunately it has been a while since I watched it, and can't give a starting point where he talks about how much it effects speed (due to callback checking, even if there is no code executed at that point).
I do remember that around 14 minutes he said something like
"If the whole web was made by CS students, it would SUCK!"
A bit off the topic, it's well worth watching even though it was recorded live, if you are at all into php/web/server/scalable/APIs. He does work at Etsy, so he might know what he's talking about :)
I would like to both apologize for the winded post and thank Mnkras for the great work he is doing for both the c5 codebase and the entire community.