you look at the way the different Mangekyou sharingans are drawn, they all have something in common.. The 3 dot tomoes are connected in some way. By doing that i think it combines all the different things the sharingan does into one.. Instead of seperating the chakra to increase perception, copy and predict and react to attacks. So by combining all that into one Tomoe you use chakra in bursts. In return you use more chakra than regular 3 Tomoe mode but the jutsu's and all abilities are increased....The 3 Tomoe Sharingan can also cast genjutsu's spells as well.. So naturally The MS sharingan's Jutsu's are Sgoing to be stronger, like Tysuokumi. I think the black whole jutsu kakashi did was a jutsu Kakashi already knew how to do. The MS just made it more powerful... Thats my theory for now anywayz..

To add to this theory, Kakashi Said i have been developing a New Jutsu.. He actually meant he developed something new.. Which means Itatchi And Madara problem can't do the attack he can with there MS yet cause they don't know the jutsu.