This is something that fascinates me, all you traditional cleaners I have 3 questions for you.
1) What is your favourite tool that you use?
2) Why is it a favourite?
3) What would be your dream tool?, something you have always thought would make your life easier or help you do a better job but no one has brought out yet.
Ok so as they say awnsers on a postcard please 
I don't do much traditional cleaning now as I started with WFP a year ago but I can answer those questions.
1) Swivloc applicator
2) Because it took nearly all the wrist ache out of window cleaning for me.
3) Two answers here. A vice versa style head (applicator and squeegee back to back) which has a swivloc type motion. Also, the same type of head where the squeegee angle could be adjusted the other way (as if there were a cranked joint on there). This would be a real bonus for tall office reception areas where the inner sill is very wide.
It's not something I would use too much but so useful to put on an extension pole for awkward windows at tricky angles. On outside windows my need for it would be largely redundant since switching to WFP. However, with the WAHD kicking in, it would be useful to have such a tool. It could avoid the need for hiring a small MEWP on some jobs (inside tall reception areas). Quality might suffer a bit but many companies would prefer that rather than paying extra so a MEWP could be hired.