Its not actually bad but it being set AFTER the end of FMP then guarantees that there will never be FMP again, ever. We fans like to cling to whatever little hope we have.
Can they even do Another without wrapping up FMP? I mean, the first thing everyone will ask is "What happened to Sousuke and Kaname?" and if they've only seen the anime, they'll add, "And Leonard?" And explaining what went down between the three of them can't be handwaved.
Especially since, as of Volume 17 of Sigma, there's a LOT that must be changed by the time Another rolls around.