srsly? Nidalee is one of the highest skill cap champions. She has multiple forms and each ability is vastly different in each form. Her dash in cougar form is very odd and easy to mess up at first, and you HAVE to hit with some of her spears for optimal play/damage. You won't kill anyone if you can't hit with a spear occasionally, and she's a lackluster support or bruiser.
I'd recommend someone like ezreal if you want to practice skillshots, since his Q is on such a low cooldown and he has an escape.
Really, 'skillshots' aren't that difficult inherently, but champs that have longer cooldown ones punish you much worse for missing them, such as Blitzcrank/anivia. Or, ones that are harder to hit/act differently then other champion's skillshots (such as karthus/cassiopeia).
Then again, some champions kits just 'feel' easy for some people. I started playing anivia very early on, even though I'd been told she was extremely hard to play, and did very well with her immediately. But, I still suck complete balls with some champs that aren't quite as 'hard', such as karthus and orianna. Landing an Anivia Q is easier for me then Karthus Q's, dunno why.
The best advice is to keep trying different champions when they are free each week. If you have the time, play each one at least twice each week while you level up, especially the expensive or new champs, as they don't come up in rotation as often. If you don't have the time, play each one at least once, but often the first time you are figuring them out and start off shitty in the early game. Then, when you get how everything works, you are behind and don't 'like' the champion.
You'll naturally develop some favorites, and by the time you hit lvl 30 you'll have a rough idea of what every champ does. Knowing how a champ plays is the best way to beat them when you start mastering your favorite champs. I couldn't lane against Zed for shit until I played him the other week and got a better feel for his cooldowns/range/etc.. for example.
I tend to play healers in most games....
As I said, I tend to play support type roles in games, so I like sticking to that. Though my fair success in killing people as Shyvana gave me some optimism.
I play support a lot myself, but you really do want to try out all the roles/lanes before you 'settle' on a role. Even just knowing what your teammates are trying to do, especially your AD lane partner, will make you a better support in the long run. Basically, don't focus on being a support already, even if that's what you eventually end up doing.