Deans might be rated for a lower current than a 3.5 plug, but the contact resistance is way better, so it will outpreform a 3.5. the deans connectors simple have got what it takes. 3.5 plugs are rather weak to begin with. the ones you mentioned are ideal for brushless motors though. (smaller ones) it depends on the tollerances they accepted during production, how good they are.
It is funny, I was just talking on Saturday with Mike to create similar thing for 5.5mm connectors with polarity tab...
- Hopefully they will cover entire family