It's not just 64 bit which people make too big a deal about. My understanding is they are trying to shift workload from the CPU to the GPU. That can dramatically improve performance. Also improving UI is important as higher resolutions are becoming more common.
I am sticking with FSX for now but I hope FSW succeeds. I would switch once the most popular addons are available. Isn't FSX still the most popular sim? I would be happy with an incremental improvement.
I think the goal is to be a consumer version of P3D which is not supposed to be used by most of the people who are currently using it (read using the academic license when most people aren't students).
And arcade games don't have radio navigation and transponders. It's no more an arcade game than FSX is.