"You sign up to be permanently the lowest level, have the least gold, obligated into the same item build path for literally every support in the game."
Part of what qualifies a champion as a "support" is the utility that champion brings to the team with their kit alone (i.e. without items). If a champion needs gold and items to be an effective addition to the team, then that champion should not be played as a support.
"You never finish an item, and "will" have on average more deaths than assists."
Wuh? If you're not finishing items, you're building wrong, and if you have more deaths than assists, you're just playing badly. This is on YOU, not on the support role.
"I feel personally that, support, (at least the supports I tend to pick) have very little impact on the game and it's just generally unfun and quite frankly, unrewarding to me."
Sounds like a YOU problem, rooted in the champs you choose to support with.
"Soraka was one of the few that gave me a real thrill playing, they nerfed her and while I do still play her, she is not nearly as impactful as she used to be."
Agreed. Sorry to hear that a champ you enjoyed is no longer fun for you, but there are still plenty of supports that do similar things. Soraka is a healbot, and unfortunately she's the only dedicated healbot in League, but many other supports offer some sustain. Sona, Taric, Bard, Alistar and Nami all have some way to heal your lane partner. Why not give them a shot if Soraka is no longer fun for you?
Also consider that supporting doesn't always mean "healer". This is not World of Warcraft. Some supports are useful for their damage (Annie, Vel'Koz), and some for their tankiness and CC (Leona, Blitzcrank). Not every support needs a healing ability to be useful.