If there was one magical speaker that could do everything and cost less than everyone else's speaker, then you'd get that answer.
The truth is, all speakers have their advantages and disadvantages. Weight, sound quality, durability, price, etc. Posting very general specs of "I want this speaker to be able to do everything" isn't going to get you any useful discussion.
The needs of a speaker for festivals and a keynote speaker in a small meeting room are extremely different. You really should have different equipment for those types of events.
+1 on the above
That being said, my recommendation for the most versatile speaker to handle the kinds of things you describe would be the Yamaha DSR 112.
Small size but big sound, can be flown, can be used on a tripod, can be used as a wedge, can be used with a sub, sounds great, reasonably priced.
Not the best choice for every single one of those applications but overall a really good choice .
