Calendar alerts - custom time, sound and snooze

I am having a huge problem with my iPhone in that the calendar alert sound is feeble and half the time I miss the event because I fail to hear it. It really ought to be customisable to play longer and have a snooze function. The other problem with the calendar event reminder is you cannot customise it to alert at a particular time, especially handy if something is an all day event (say a birthday reminder) and you want to be reminded at 9am about it - instead it goes off at 12am...

Does anyone know if these are going to be dealt with in any future upgrades?