For me Siri does this....
Siri will tell me whatever about the weather, from what will the temp be at 6am tomorrow, to is it going to rain. So weather is covered.
Siri will set, erase, edit all alarms. So alarms are covered.
Siri will set reminders and calendar events, etc. So Reminders, Calendars, etc are covered.
Siri will read all specific stocks and tell you by voice. So stocks are covered.
Siri will send all texts from speech and read unread text messages. So texting is covered.
Siri will play whatever from your ipod/Music. So music is covered.
Siri will give directions by your speech to where you want without issues. So directions,maps are covered
Siri will dial all calls, from names, nicknames, relationships, or by saying the numbers. So phone calls are covered.
Siri will set a timer for you. So timers are set.
Siri will give you useless cooking information, how many quarts in a gallon, etc, stuff girls will use. So thats covered.
So what is Siri lacking that isn't aleady covered that you are looking for. I did have to talk to Siri so it can adapt to my accent, speech patterns, etc to make it more accurate. Probaly a 95% accuracy for me on all words now.