How you're getting that out of my answer is beyond me, but to a degree all champions are just one button bots at the end. By Interactivity, I mean to say what they contribute to teamfights in the mid-late game, the early game does not really matter because you're pretty much just watching lane for the most part and not doing much. Yes you poke here and there, but for the most part it's just farming simulator.
I have a weird definition of what interactivity is in that what are they doing when it comes to the fights. For a champion like Sona, for example, all she does is W constantly to make sure her team is topped off. The Q part does add damage and her ult is a CC engage, but really in fights the ones I've seen are in the back with their green aura. They toss out a Q here or there, but it does not feel like you are contributing much to the teamfight.
As for Soraka, she just heals, heals, heals, ult heals, heals. Does she do damage? No. She has a silence and stun that doesn't seem to do anything (although that's just me, enemy Soraka's seem to constantly get that thing to stop me dead in my tracks so I'm a bad soraka player)
I'm not saying "Oh, they must be flashy, damaging blah blah blah" it's that I think there should be more supports that provide more than just a stun, just a shield, just a heal. In the Case of braum, he has the stun, shield, and knockup, but he can jump into fights to engage/disengage, shield a full MF ult only to turn around a fight to send the enemy running. Bard provides extreme map presence with his E and R because his heals are so pathetic (does it even heal? I think a fully stacked shrine barely gives me a sliver of health, it's better for the movespeed buff)
I don't mind playing Sona, I don't mind playing Janna, yes I play Lux but that isn't the only one I play support. I like playing Leona and Nami because they feel far more interactive than Sona or Janna (yes, I'll say she's kind of uninteractive because all she does is shield and ult. I think her tornadoes are better as a zoning tool than an engage/disengage unless I'm quick-firing the thing)
I was a Support main back in Season 5, I'm a support main this season, to call supports uninteractive is not really the proper word for it, more rather they don't feel as rewarding or useful with champions like Ivern coming in with his massive shields, Yasuo who windwalls and flings around, Malzahar who ults, silences and has his pokemon attack you.
Damage =/= interactivity
Heals/Shields/Stuns =/=Interactivity
Diversity of kit, IMHO, is what I feel defines interactivity.
As a support, I don't want to simply be a ward bot, I don't want to watch health bars to make sure they're topped off, I don't want to sit back and wait for an opportunity to lock down a target. I want to be in fights, I want to be doing what I can for the team, I want to feel like an actual player that's scrapping, kiting, locking down. Playing Lux, for me, provides the perfect amount of Interactivity as a support because she can stun, she can peel, she shield, she has slows and damages, I can play as passively or as aggressively as I want and not locked into one type whereas most supports encourage a more passive playstyle from my experience. Leona is my go-to for a traditional support if my team asks me to not play lux because she can engage, disengage, peel, fight, or tank as needed.
That is what I mean by interactivity from my perspective, if you want to dumb it down to "OMG, they don't do damage," you're clearly missing the point of my post. I'm not saying I want to do damage, I want to be able to do things in case my team fails somewhere. Try carrying your team as Sona when your mid is down 100 cs, your ADC is AFK and your Top is a Yi who rushed an early rageblade.