...I hate to fashion myself a newb, but blast zones? What's wrong with fast rolling? Shield dropping? What's dash dancing??
Blast zones are the areas at the edges of the stage (bottom, sides, top) where if you hit them then you lose your stock (die). Some people don't want them to be too far away because that implies the games can take too long to actually land a KO, instead you'll just hit people far away but they'll still survive and have to move all the way back to the stage to keep fighting.
Fast rolling: I'm not sure why some people don't want this, but maybe just because it's kind of a weird game if characters just spend the whole time rolling around everywhere instead of, y'know, walking+running which give you more versatility about where you go. If everyone's rolling all the time it also seems very defensive because you're invincible during that time, it might slow things down but also limits everyone's options.
Shield dropping is just letting go of your shield and doing an attack. In previous games there have been ways to drop your shield quickly; e.g. in Brawl, you can jump or upsmash directly out of your shield. Simply letting go of the shield causes "shield-drop lag", some frames where you can't do anything. But the up-smash or jump can come out
immediately out of the shield, so you don't waste any time, so those are better offensive options out of shield.
Dash-dancing is where you knock the control-stick side-to-side really fast; in previous games you would dash one way, then the opposite way, really super quickly (no time wasted in a turnaround animation), this makes it hard for the opponent to space against you and predict which way you are going to go / when will you attack. If players have lots of movement / running / dash-dancing options, it gives the game a faster more dynamic nature at high-level play.