That's something I've been thinking about to, but we can't seem to add everything from the Uchiha clan.
Firstly, who would pick it, if after a while you need up going blind, and losing the power, if not worse than when you started, but let me think of some things we could do to make the Uchiha Clan more Cannon, yet still playable.
So, first of all we have Susanoo, which this topic is about. We know it is one of the three main Uchiha Dojutsu accessible via the Mangekyo Sharingan, so really it should be available, especially since it has appeared in the Anime now. I still think it needs training as Sasuke is shown he needed to train it before he could use it's full power. Teachers could Itachi or Madara, I prefer the idea of Madara myself.
I stated above my ideas for the buffs, but I'll restate it here. Three levels training,
-Level 1: Cost 15 Chakra points, to get a defence buff, maybe double, but half attack. At the first point Sasuke created a partial Susanoo which provide some protect, but would have limited movement for attacking, last for somewhere between 5 - 10 rounds.
-Level 2: Cost 15 Chakra points, Invulnerability for 5 - 10 rounds, and still an attack decrease. Sasuke could form Susanoo, but still not really use it's full power, and still can't really attack himself.
-Level 3: Cost 15 - 20 Chakra points, Invulnerability for 5 - 10 rounds, plus either an Attack increase, or the buff causes damage. At it's full power Sasuke could be protected, and attack with it. This level may also cost perm. HP when used like some other things.
Now, when you think about it, we still have other Sharingan things that could be added, but some we don't know much about, but I'll list some here.
-Sharingan's copy Jutsu ability: Now something that could be done, would be enemies in the forest with Jutsus, for x Chakra you could reverse, or counter their Jutsu. Same rules apply as to normal use in series, ie can't copy KG's.
-Kamui, Kakashi's Mangekyo Jutsu: Not much is known on why Kakashi can use it, and if others can.
-Madara's Teleporting and Phasing abilities: Again, we don't really know Much about these.
-Izanagi, possibly a Mokuton/Uchiha combo jutsu: Again, a bit known, another invulnerability buff, maybe even escape Enemy Jutsus, but would have to be heavy cost, ie weakened or no Sharingan buff until next kills.
Also, when then have to consider things such as Mangekyo blindness, and the Eternal Mangekyo Sharingan.
Well, seriously, we couldn't make all Uchiha uses go 'Blind' after x uses of the Mangekyo Sharingan, as that would just be unfair etc... What I thought was maybe, each time you activate it, or use one of the Jutsus, it lowers the buff received, even to the point of making you have a debuff to a certain point, ie blindness and it can't go lower. However this would be removed at your next Dragon Kill.
As for the Eternal Mangekyo Sharingan... not sure if we really should had it, as well still don't really know a whole heap about it. Maybe we could make it some really had series of events, like finding you have a brother, tracking him down, waiting for him to reach Mangekyo, eventually killing him in an all out brawl in which he has all the Mangekyo Jutsus to use against you. Then all it would do would just stop the blindness thing.
That's all I can think of at the moment, but when you look at it, most of the KG's now have things which could be added to them due to progression in the series... I think the Hyuuga have a couple of jutsus that may not be in there, as well as the eight gates, but they aren't my area of great knowledge.
Just some ideas to throw out there, any other thoughts?
