The loss of downtube shifter also meant the loss of some interesting cycling skills.
Double shifting with one hand. Slamming the shifter all the way forward on a big sprint. The need to be able to set the front derailleur trim the first time.
Lot of cool one hand gymnastics have gone by the wayside.
I raced friction up til about 1994, before I went to STI. Not a huge disadvantage. But the STI is just so much easier. I won't be going back.
-Z