have u tried it before u reply? and yes i did tried ad + support but u cant always have good supports in your team (i mean not feeding , not last hitting doing their job properly i think u get my point)
have u ever tried having 2 ad champions in your team with 2 starks fervor? let me just tell u that even champions like "veigar" will leach like 50 hp per normal hit (i set veigar as an example cuz u rarely play with normal hits)
(cait+vayne were examples its true about minions though they can push and make enemy champions stay back all the time losing xp and gold, also note that vayne has great mobility while cait has great range which makes her a supreme pusher , a combo of these two owns , i ve tried this by myself)
im sory for this long reply and im sorry for going off topic :(