The MSQ story dungeons and trials weren't much harder, but their pacing was faster, and if you're already used to the types of mechanics then it won't seem nearly like the change you want.
MSQ should provide an okay challenge, but you need to put context to your 0-10 scale because if players only do MSQ and maybe extremes, then their 0-10 is MSQ to EX, where my 0-10 is MSQ to Current Patch Ultimate, which are two completely different scales.

Not all content needs to be ball crushingly difficult, but not all content needs to be super easy either. If you want a more intense challenge, commit to savage or ult raids that are made specifically for that reason with rewards to match it's difficulty.