In my current games i'm upping the challenge by, besides using set instead of switch, evening the nº of pokes with the gym leaders. Against E4 and champion i use a full team. Also i use only 1 item from the same type, equal or weaker than the gym leader and no overleveling, the max level is the level of the strongest poke of the leader. In BW2 it's still easy to beat them, all but that d1ck drayden with DDance (because of that huge level jump since skyla).
I also rotate and not knowing all the pokemon that could appear, if i like a guy i catch later in the game and i have a full team i like too, i will most certainly rotate.
My point with this is, bring hard mode from the beginning, with a harder AI, good movepools and items (all different like competitive) and we don't actually need higher levels with all the above included, don't bring easy mode back because normal mode is already easy and make the level curve less abrupt (skila to drayden in BW2). Also, the contest/musical/cinema should be tryathlon like HGSS or some other minigame facility because it was awesome back then and it still is.