As you've been having the same problems as me and lots of others(!) I would agree that you've been right all along!
I would take your car in to your local Ford service dept and ask them to change the indicator stalk as it isn't normal or fine!! As a bit of extra info having driven my car lots more today since they fixed it yesterday, it seems they've replaced the indicator stalk with a different type/style one (or fixed it to feel and act differently) - as in there's now (thankfully!) no flick it lightly up or down for 1 or 3 indicator flashes - or continuous when it decides it actually wants to stay on indefinitely! :s I think this is where the problem stems from personally. It's now just up or down and it cancels itself perfectly through just steer alone, just like it should and how every ford I've ever bought and driven before has! As for why they decided to add this extra feature I've no idea as it just seems to have caused everyone a whole lot of hassle, confusion and self-doubt! I mean in what situation would a single flash of the indicator be of any help to anyone anyway???! 3 isn't that much more helpful either really! I think 6/7 before a junction/roundabout etc is about right. Anyway, book it in with them and mention my post and say it's not normal nor fine and you want it fixed!! I used their Epping branch 01992 577615 so maybe refer them to the engineers there if they're not sure what to do or how to fix it as they fixed mine perfectly so should be able to fix yours and anyonelse's too! Good luck and let's hope we're the first of many, many fixes!
PS If you want/need me to find out exactly what they did I'll gladly pop in and speak to them to find out and post full details on here as I just wasn't sure if this was still a problem or not as the original posts were so long ago.