IIf I want to use a Moyu big cube with stickered corners and edges and stickerless centers, is that legal ? I guess it is, because the issues caused by stickerless cubes don't come from centers, but I would like some kind of confirmation. Thanks !

3d) Puzzles must have coloured parts, which must be one of the following: coloured stickers, coloured tiles, coloured plastic, or painted/printed colours. [b:2wwwojxa]All coloured parts of a puzzle must be made of a similar material.[/b:2wwwojxa] 3d2) The colours of puzzles must be solid, with one uniform colour per face. Each colour on the puzzle must be clearly distinct from the other colours. Based on these regulations, I would say it's not legal.

As hcfong replied, Regulation 3d) does not allow this. In addition, Regulation 3h2 also technically doesn't allow this: https://www.worldcubeassociation.org/regulations/#3h2