It looks like Mario Kart 8 Deluxe has a few changes in store for higher-level players. In Mario Kart 8 for Wii U, players found you could actually gain some speed if you hopped in alternating directions after a mini-turbo speed boost. GameXplain has tested the method in Mario Kart 8 Deluxe and found that not only is fire-hopping not useful in the new version, but it may also be a hinderance.
The reason for the change is likely two-fold. One, Nintendo probably didn't intend for the technique to be used in the first place. In addition, fire-hopping didn't work on bikes at all, so that effectively shut out those vehicles for expert play.
Two, Nintendo has already added a second level of speed boost to the game. In the original Mario Kart 8, you can tell what level of mini-turbo you'll get out of a drift by the color of your sparks: blue is for the first level, yellow is for the second. In Deluxe, there's a new third level, denoted by purple sparks.
You can see Nintendo showing off the new mini-turbo in the video below.
That's not to say the veteran Mario Kart players won't find a new exploit technique in Deluxe, we just don't know what it is yet.