Island Tour's boards feels like it doesn't matter what you do in-between sessions, and there's always a single ridiculous gimmick in nearly all of the boards that make them far too heavily reliant on luck for, I feel, like players to put in any actual effort to winning the game. I mean, I get that it's Mario Party and there's always going to be luck involved but I feel like Island Tour ramped it up to extreme levels to, like, why do I even bother trying to win minigames any more when the rewards aren't that great or there's luck-based elements that hold it back (and many boards don't even feature minigames to begin with).
Perilous Palace Path, in theory, you should be able secure a lead by winning the minigames, getting Gold Dice Blocks, and earning items, but the random events in the board like the Thwomp and Goomba Tower equalize it out far too much in favor of the lucky person.
Rocket Road lets you roll zeros when you least expect it and eat up all of your boosters and otherwise lasts far too short to have any significant impact on you. If you roll a single x5 Booster on the higher numbers, you win the board, that's how short it lasts.
Banzai Bill's Mad Mountain has you praying someone doesn't roll a Banzai Bill or land on the Banzai Bill space at the wrong moment. That's pretty much the entirety of this board.
Kamek's Carpet Ride is probably the best one with its Power Precision and Precision Cards but it's still heavily luck-based.
Shy Guy's Shuffle City isn't even available to single-players, subtracting board count total.
Star-Crossed Skyway, the one board that could good use of minigames every turn and an item system, doesn't feature minigames and items and instead relies again on luck to reach there where desired, either first or last (or land on the swap spaces) to get the most Mini Stars from the Mini Star Stage stuff.
Bowser's Peculiar Peak lets players be safe when you roll doubles, actually placing first in minigames in a round of four players is actually pretty bad since you avoid rolling doubles. There's also a lot of luck-based board elements too like the bomb blowing up the wall thing and the final Bowser challenge.
I do agree the quality of the minigames is much better in Island Tour, but Star Rush also had Coinathlon and a much stronger board gameplay mode, something I feel contributes to a stronger experience with the expense of fewer minigames. Balloon Bash and Mario Shuffle is both pretty ass yeah.
EDIT: If you want an Island-Tour style race to the finish board done right, look no further than Mario Party 5's mini-game circuit in the Mini-game Mode. That mode awarded you items when you win minigames. No extra frills or nonsense attached to it like in Perilous Palace Path. No Goomba Tower junctions or Thwomp switches.