Oh yeah, I agree. I play jungle and top mostly when I solo or duo, but I main support in our ranked 5s (so I may perhaps be a bit biased). There are times when I tower dive to allow my ADC or another teammate to gain 2 or 3 kills and come out with either a sliver of health or die in the process (I try my best not to).
I'm a Leona main, I understand that feeling. I play a little too aggressively sometimes, purely because
I'm Leona and anyone who comes near me is my bitch. I was playing with my ADC in practice normals and I surprised him with something he told me afterwards he'd never seen anyone do before. That game, we'd laned against a Caitlyn/Blitzcrank, and the enemy Elise was ganking. We were pushed back under turret and the Blitz threw out the hand to grab him. I saw it and flashed into it to save him, and yelled, "Follow up!" over Skype. After the pull, I threw out an E to Caitlyn and proceeded to stunlock her and pop my ult. One of the best triple assists I've ever had.
I know things like that are hard to do in solo and duo queue, but I think with flashy and tanky champion supports like that, it becomes easier to carry the game in your own way, especially since ADCs are (theoretically) better at higher elos and able to understand when their support is going to engage. I do think that all roles lose a little something in soloqueue. I feel it myself when I play with and without friends - it's why I rarely ever do soloqueue.