I understand wanting D3D9 as an option, that is a very valid complaint. But I actually have an answer for you.
D3D9 doesn't support integer math at all; which is what Dolphin was moving to. Because there is a shared video common in Dolphin, changing everything to integer math means D3D9 will no longer function. Technically, it would have been possible to completely isolate D3D9's code or something, but it would have taken a tremendous amount of work, it would have received none of the upgrades, and become even harder to update and upgrade due to using completely unique code.
D3D9 was removed mostly because if it wasn't, D3D11 and OpenGL could not continue to improve. This was a difficult decision, and took months of thinking, working, and even going back on the idea once. But in the end, there wasn't enough interest in D3D9 to justify the absolutely huge amount of work, especially when you consider we archive older builds that still have D3D9.
tl:dr; D3D9 wasn't removed to force people to use D3D11, it was removed out of necessity.
D3D9 doesn't support integer math at all; which is what Dolphin was moving to. Because there is a shared video common in Dolphin, changing everything to integer math means D3D9 will no longer function. Technically, it would have been possible to completely isolate D3D9's code or something, but it would have taken a tremendous amount of work, it would have received none of the upgrades, and become even harder to update and upgrade due to using completely unique code.
D3D9 was removed mostly because if it wasn't, D3D11 and OpenGL could not continue to improve. This was a difficult decision, and took months of thinking, working, and even going back on the idea once. But in the end, there wasn't enough interest in D3D9 to justify the absolutely huge amount of work, especially when you consider we archive older builds that still have D3D9.
tl:dr; D3D9 wasn't removed to force people to use D3D11, it was removed out of necessity.