Well, luffy already does something like that via haki hardening. I am not sure if becoming harder than he already is thanks to haki would be of much use. Its a viable explanation though. And that would work too with my idea 




. And I think it would be wise to change the title of the thread to avoid confusion. Unless you really plan of discussing what Gear 5 will be like after Gear 4 is revealed of course.
The time luffy receives gear 5 or something along those linesWhat title should I put instead?
Already took care of itWhat title should I put instead?

I fail to believe that DD will get crushed by Kaido easily, imo it will be a close match. Your assumption of DD losing to Kaido is when law told DD that DD is scared of Kaido and your conclusion to that statement is Kaido rapes DD (effortlessly)! Why don't you consider some other reason for why he is scared? DD is very strong, near Admiral level and he knows what Admiral level is. He is not scared of Fujotra and Aokiji as we have seen. He is also confident that he can kill fujitora and as I said he knows what an admiral is capable of so he is most likely not bluffing.Of course there will be a Gear 5. Luffy is about to use his Gear 4 against Doflamingo, someone who would easily be crushed by Kaidou, Shanks or Blackbeard. How should he survive against these 3 with only 4 Gears if he has to already use Gear 4 against Doflamingo?
About when he will use/show it: I think he already learned Gear 5. He trained for 2 years, 1 1/2 was Haki training, so that makes 6 months of Gears training. A much bigger timeframe than when he learned Gear 2 and 3, from the defeat against Aokiji until Enies Lobby, giving him enough time to master Gear 2+3 and learn the new Gears.
I think Gear 5 is something for a situation where no other option is left, because the the backlash of Gear 5 is something that will make Luffy go out of all energy and collapse. Against the birdcage there are still other options left like Fujitora, Zoro or Sabo, but against Kaidou who would be only 1 second away from killing a Strawhat Gear 5 is the only option, do or die.
Emperor level is something you earn yourself if your and the strength of your crew equals that of Whitebeard and his crew, something Blackbeard did by stealing his power and assembling a crew consisting of the most dangerous prisoners of Impel Down. You can't call yourself an Emperor if you don't have this strength, and DD does in no way have such a strength. The fact that his whole crew got annhiliated by the Strawhats and some other pirates which are below the Strawhats in the term of strength and that he got serious wounds from Law is proof of that.I fail to believe that DD will get crushed by Kaido easily, imo it will be a close match. Your assumption of DD losing to Kaido is when law told DD that DD is scared of Kaido and your conclusion to that statement is Kaido rapes DD (effortlessly)! Why don't you consider some other reason for why he is scared? DD is very strong, near Admiral level and he knows what Admiral level is. He is not scared of Fujotra and Aokiji as we have seen. He is also confident that he can kill fujitora and as I said he knows what an admiral is capable of so he is most likely not bluffing.
We still haven't seen what gear 4 is and you are already assuming that it is weak and not able to keep up with a yonko. What if gear 4 is hella strong? Then there shouldn't be a possibility of gear 5.
Emperor level is something you earn yourself if your and the strength of your crew equals that of Whitebeard and his crew, something Blackbeard did by stealing his power and assembling a crew consisting of the most dangerous prisoners of Impel Down. You can't call yourself an Emperor if you don't have this strength, and DD does in no way have such a strength. The fact that his whole crew got annhiliated by the Strawhats and some other pirates which are below the Strawhats in the term of strength and that he got serious wounds from Law is proof of that.
Fujitora is a new Admiral, and he doesn't even take this whole situation serious. Aokiji is the same, he didn't want Smoker to get killed, but he also didn't want to seriously fight DD. Someone like Akainu would have crushed him in a matter of seconds, Akainu fought for some time during Marineford War alone against Whitebeard and after his death he didn't stop form chasing Luffy and attacking the whole Whitebeard Crew, so DD is nowhere near the strength of a true Admiral, someone whos mission is to kill/defeat DD.
Why do i think there will be Gear 5? Easy, Luffy has to use Gear 4 already against someone like DD, someone like I pointed out is not as strong as an Emperor or an Admiral. And do you really think Gear 4 will be enough for the 10+ years of One Piece, that Luffy only needs to train for 2 years and he already can fight Emperors and Admirals? His Gear 4 is something which was developed in 6 months, which makes it even more unrealistic that Luffy is already strong enough to fight these strong enemies, with only 6 months of training.
Kaidou didn't try to kill Whitebeard AFTER the War, he tried to fight him BEFORE so that he couldn't save Ace.First of all, Kaido is not WB level. WB was on a league of his own. Kaido could be seen as a coward as he planned on attacking WB and his crew after WB was tired from battle but BB got the jib done.
You did not read my comment properly (maybe you did), I said that DD will not be defeated easily as you said he would. I never said that DD crew equals Yonko crew. I find DD’s pirates to be exceptionally weak compared to what DD is capable of. But DD is very very strong. As fox666 said he walked out of the marineford war alive and unscathed. What makes you say that Akainu would have finished off DD very easily? If you do have proof then show me and I will believe you.
Also you underestimate Fujitora on a whole new level. Mate, he is an ADMIRAL! Doesn’t that say everything? He was handpicked by Akainu himself, so surely he can’t be any bad. His fruit another admiral class hax fruit. Also Akainu respects him, we can see that when the news came that DD’s title of shichibukai is still there and Fujitora did not know of that so Akainu apologised.
As i said we do not know what gear 4 is capable of so it's still early to judge. And why does everyone forget how quickly luffy improves? When he went down Impel Down it took luffy+buggy+Mr2+Mr3 to take defeat THE MINOTAURUS. After less than a day later when he climbed back up, he dfeated it with just one punch.
I tell. Even for One Piece standards, which characters seems to be fine after all sorts of fatal wounds, Law attack was brutal. Doflamingo is the only one who could survive having his internal organs sliced.And don't tell me that Laws "Gamma Knife" is stronger than a full power tremor hit from an enraged Whitebeard, because it isn't.