Sounds like you should be posting this in the New Player Help forum. You should post it as a questions about, how can I improve my SP gain during leves. Which leaves me to the point that the Dev tag isnt' required. Looking for a good Linkshell would be a great option too. Don't forget, there are also Behest you can do in between you Leves which is some great party play.
First off I am not a new player, I have played FFXIV since the alpha. I been playing FFXI for 8 years, my FFXI linkshell had many server first kills Tiamat, Jorm, and Vrtra to name a few. We started with a linkshell made up of mostly FFXI players and some friends 39 people in total. They all quit playing except for like me who occasionally logs in. Most of them went back to FFXI or WoW. So when virtually all the people from a server first linkshell quit, yes there's a problem with the game.

This does need a dev tag because it needs to be read by a dev because its a problem with the game. Using the features in the game progression is just way too slow by today's MMO standards.

^ these 2. Don't do leves alone, try do it in party with some leve link.
Trust me, exp/rp are far from low
Sounds like you soloed them on one star.... dont do that
Sure maybe being in a party would result in faster kills and more exp just like in FFXI, not arguing with that. However there wasn't any people on the game to do these with. I am not talking about people in a linkshell since mine is empty but random people. I saw 0 people by the Nophica's Wells crystal and about 3 AFK people who were in the Nanawa Mines camp. There wasn't any other way to do these but on 1 star and even then they are pretty hard because a gladiator doesn't pull the highest damage by any means, and I am rank 28 and it says they are for rank 30. 2 star or above would result in me getting killed very fast, I still died a couple times on 1 star. Even on 1 star the imps can hit me for 80% of my HP with their special attack.

I am using the resources and people available in the game at the time I was playing to the best of my ability and my experience was not good which is why I am hope a dev reads this. There needs to be adjustments because people will have times they log on and see nobody in their level range doing these quests and have no choice but to solo them. SE wanted this game to be easier and more friendly to people trying to start out but it really isn't and they really need to lower the sp and exp curve.