I don't know how usueful this information will be or even if anyone else still uses FSW today but here goes,
I recently discovered (by chance) that VFR flight plans from FSX SE work without any changes in FSW. This means that I no longer have to use FSW's awful flight planner, instead I simply create and save a FP in FSX SE then copy/paste it direct to my FSW sim, choose an aircraft, set the weather and fly!
I haven't as yet tried IFR plans as my personal taste is for smaller birds that don't use it (plus I don't know how to fly IFR yet! )
Again, I don't know how useful this is going to be to anyone else but I thought I would just put it out there for you guys to read.
Keep flying high,
Thanks for posting this, we can hope it will help others.