I see two valid reasons (left) for Multisite:
1) Franchisor/Franchisee setup (ie: the parent site has a ton of child sites that are run from the top down or are essetially cloned from the parent). This includes university setups in some cases.

2) Product Demonstration sites for software companies (I use it for this purpose with a custom "brew" to make it happen). The lower overhead and shared resources make this efficient (But frankly there are newer and better ways to do this by spawning clones from an original parent into single sites)

I don't think there is a need to "kill off" Multisite, but I do find that for all other uses than those above, it is a better solution every time to clone/create a new single site and manage a bunch of them via ManageWP, MainWP or similar dashboard utilities.

Many folks still don't realize that Multisite commits one (Forevermore...) to a shared database and other limitations discussed in the article. It's not as frequently requested as in years past, but I do still spend a fair amount of time explaining the issues above to the uninformed.