1)First off how about some new outfits?
Outfis I recommend would be:
From naruto: obito, reanimated itachi, sasuke with his eternal manegkyo sharingen
From one piece: brook, doflamingo, akainu

2)The hogyoku system:
This was a system that existed when the english version of this game was still up. Basically it's another tab in the pet kennel where you have your pet and 9 slots (I think it was 9) surrounding it and is pretty much shares the same function as the bankai tab. You can get packages (up to you on how to obtain these packages. Could be from silver shop) that can give you either a green,blue, orange or red (lowest rarity is green and goes up in order) stone of some sort that boosts one stat (hp,speed, strength, armour break, agility, defence etc.)which you can place in the slot. You can upgrade these 'stones' by gaining hogyoku essence (I suggest 1 bag contains 3000 essence. (Sort of like the spirit stones for the zanpakuto tab). Now for how high you can level up these stones I'd suggest anything from 60-100. Basically, this whole function is just another way to boost your stats. I just think that this will give players something more to work for and to be stronger or the strongest.

1) Maybe
2) No