Its only a concept but we should make it possible, being able to learn a jutsu form doing a set amount of things then acquiring the skill. Example would be you have run for a extended period of time and have done a lot of parkour so lets say you learn the run on walls technique and while i'm discussing such topic, how about you have to learn how to run on water as well, so you can't travel to certain places until you have the proper jutsu to get there.

New way to learn Jutsu
A new realism way to learn jutsu is actuelly having to have the person remember the jutsu even in battle, When first learning of a jutsu they recieve a Scroll.
This scroll reads them how to use the jutsu for example (You have learned: CHIDORI, The jutsu seals are  Ox>Hare>Monkey:Enter        Remember these signs.

The scroll can then be put into a bank or a house for safe keeping. To use the jutsu people mold those signs. But if they forget it there is no quick menu to learn it again. they must go back to the bank and learn it again.

They can see the strenth or level of the jutsu in a menu but they can not learnt he hand signs from it.

Elemental Combination

The allowing of tag team with elements, say if someone was hit with a damaging wind feild, and someone shot a fireball in it. the fireball would then be 1.5 or 2x stronger then before

Or if someone is hit with a water attack and becomes soaked then someone strikes them with lightning.
the lightning would have a paralysis effect with 1.5x damage.

These are some ideas, Do comment your thoughts

Now this may be already taken in to question but I think this could balance the game a lot.

I don't know how it will be implemented but maybe you can hunt animals or fish and sell it at a market. Or say eventually have the currency player based, where people can hire other players to spy on a person/ Village for info on something they want to know for maybe a raid or seige.

This in game money can be used for a number of things, Say items. (Weapons, Bandages, Food, Clothing) or Less more realism things ( a stay in the inn to revive health or lost stats threw dying and reviving in the village)

Either way I feel these could be a big help with the whole MMORPG feel but being thrown in to a MMOARPG, Like posted in a previous statement of Vreg, That you can loot any items off players. Well how about money be one. Have a village bank and you can store money's in either your home or the village. So if you want to get that money back you need to return to that village thus if you want to travel with large amounts of money you may want to hire people to assist you in transfering it in fear of ambushes.