I don't know if Enhanced Economic Activity is a Mega Event or not but i find this event too much overpowered.Since i got DA in all my games i got this event and i always go from -20 or -100 bc to +300 or +600 bc.
I don't know if there is also a "Economic Activity worsened", but aren't these effects too much exxagerated?
In my last game that event lasted for a lot of turns and i went from a struggling economy at 1500bc to 32000bc, no need to explain effect on game.
If the effects are +100% or +200% or +300% wouldn't make more sense to tone down its effects?