I haven't even used a mega yet.
It is too easy the caves are not mazes and the opposing trainers never have more than three pokemon! Back in my day, trainers had 6 and made you leave a cave several times to heal before making it to the next city.
Ikr? And Mega Evo's are too fun. I always use Mega Blaziken. I still remember doing all that with Blue back when I was little.