You can only use ultimate attacks when both you and your opponent enter "Spirit High." This can only be achieved when one of you loses enough health to be in the red (the ball at the top of the screen near your health turns red). This makes it so ultimate attacks CANNOT be spammed nor can they be thrown about whenever the player wants. You have to build your way there and strategically decide when to execute it. Very different from the previous titles but I welcome this new change as it's a big middle finger to spammers.
"you CANNOT SPAM COMBOS... its impossible... it ruins the meaning of the word."
Over using anything can be considered spamming... even the same combo over and over. If someone did the same thing over and over in a fight in the real world, wouldn't you think "lol, that's f**king cheap, he should do something different"? Spam is spam.