I still don't get how you can argue that the devs should axe the raid mode with the highest percentage of completion simply based on some feeling that it's "killing the midcore/hardcore scene". If WoW suddenly lost it's ridiculous amount of funding and had to scrap one of it's four raid modes, I can assure you that LFR would not be the mode to go.

I don't think the hardcore raiding community will quit because there's a story mode raid, they'll quit because raid content in this game is laughably sparse in general. There's four bosses every 6 months that, when on farm, will take you one evening to complete. Given tome caps and terrible drop RNG, a hardcore raider will be BiS in a maximum of like five months. So one month of gearing an alt job, if they even care about it, all to have the gear replaced with the next tier.

Don't fixate on story mode, it's not the problem. General scarcity of raid content and constant "gear resets" are. SE's IMPLEMENTATION of releasing story mode first and making people farm it for relevant gear is pretty bad design, but it's very existence isn't.