Crusade needs an actual competitive community before they can even think of making a tier list.
Right now, Crusade is mainly popular for its modding potential for adding more characters (like a knockback platform fighter MUGEN).
"This game is excellent but it need a better online system"
"and why this game is still only on Windows and isn't on Mac and Linux"
- Both are probably because the game was originally made in old Game Maker, so its ability to support fancy new features like multiple OS support and modern online netcode is inherently limited.
"and also it would be nice to have a tier list that sort out every single character (for example S tier: C.falcon...)"
- That's only ever determined by the players, not the devs.
"Please add an option to make it more/less sensitive"
There is lol.
"Another quick thing - maybe add a short-hop button and allow you to short-hop by tapping 2 jump buttons."
That input method is awkward AH. Just having minimum/universal 4-frame jumpsquat is good enough (yeah I don't like Ultimate's 3-frame jumpsquat either).