"Happy hour" wouldn't work because people play from all over the world in these servers so it would be highly unjust. That's why there is LM (lucky moments) every now and then. There has always been rewards for new starting players - they get all sort of things like pots, costumes, gears, crystal chips, discount coupons for CS, xp and rep scrolls etc. They change almost yearly.
What comes to free events in general - I agree, that there isn't very many. Some stuff in guild portal and the yearly events like design a swimsuit, PMB etc. Although I must praise the Task Force event we're having now.
But I wouldn't want to have an event every week - there's so many CS events already and in too fast pace.