While I think this is a great topic, and it's real awesome that we are agreeing on something here, but there happens to a glaring issue that has yet to be touched on.
While people can be like, "I'm going Sixth gate, Sage mode, and RNY, then I'm gonna run at you from 10 feet away with Shunshin!" I can guarantee every single one of you will react. >> The problem isn't with people stacking it's that there is an overall disconnect on how fast things/people actually move, and what is actually possible to react to. No matter how fast ANY of us move, it does not matter at all, a reaction will ALWAYS be made. This topic cannot accomplish anything unless Mr. Bocchiere teaches the populous Physics, and the science of EVERY relevant body part that is involved with reactions, and reflexes.
But that aside, yes, even logic alone makes it pretty clear there's only so much the body will take before muscles are absolutely shredded and bones smashed to powder >_>; Gai's a good example, even lifting his arm after 1-speed Evening Elephant fractured his arm, and he wasn't even stacking...
If 'logic' is being used as the basis of this argument, and oh boy that's a path we want to go down. Sage mode gives passive durability, one that has never been elaborated (To my knowledge) other than the ONE instance where he falls on those spikes. If durability of muscles, and bones is the basis of the argument here, then we must not just omit the fact that Sage mode users are afforded a certain amount of resistance or some durability.
Gai for instance in the 6th gate can ignite air with a punch. To do this, his fist would have to travel at roughly twice the speed of sound (I've done the calculations >> Ask Rusaku), and yet there were no sonic booms, no HUGE walls of air surrounding his fist as they should have. This was ONLY 6th gate, and already the bounds of reality have been broken.
If this comes to pass, Sage mode users get nerfed extra hard. We ain't got shite worth talking about over Rinny users if our speed is taken, oh our jutsu is supposedly 3x 'stronger', Oh we are supposed to be able to move real fast, and be real strong/durable? The majority of Rinny users 'match' any of that through training anyway? (You know you do it >>)
And apparently all men are created equal here, and we all based our characters off of Gai, because he is being used as the baseline which makes for a disingenuous argument. There are people running around claiming all kinds of immunity, and passive nigh-impenetrable durability. The fact of the matter is, the standard here is higher than the Naru-verse. People claim all kinds of shite that breaks the supposed bounds that we all 'MUST' abide by, some people even claim 'variants' of banned Rikudo/Sage techniques anyway, so all I am reading here is. YEAH NERF SAGE MODE!
TL;DR: Nah dawg. Unless fair compensation is given to retain the relative balance between Sage Mode V. Rinny.