Joined: Aug 2010
Posts: 12,727
Likes: 2,105
From: Madison, WI
Bikes: 1961 Ideor, 1966 Perfekt 3 Speed AB Hub, 1994 Bridgestone MB-6, 2006 Airnimal Joey, 2009 Thorn Sherpa, 2013 Thorn Nomad MkII, 2015 VO Pass Hunter, 2017 Lynskey Backroad, 2017 Raleigh Gran Prix, 1980s Bianchi Mixte on a trainer. Others are now gone.
I would NOT change the chainrings from half step gearing.
You mention Suntour bar end shifters. Less common but good bar end shifters were also made by Shimano. Suntour had a ratchet mechanism, Shimano instead had return springs built into the shifters to counter act the springs in the derailleurs, allowing a light friction setting. Both Suntour and Shimano friction shifters would be a very nice upgrade.
From the photo it looks like a Suntour LeTech front derailleur. If so, keep it. I found some new old stock ones and bought a lifetime supply for all of my bikes. I have a strong preference for high normal front derailleurs.
I know what you mean about shifting, I prefer index shifting. But I have not sold my 61 or 62 Italian racing bike because I like the old classics.