Help me pick out a new main!

Hey, So I'm giving up Diana after 300k mastery points, I would really appreciate if a higher elo player helped me make a decision since I'm stuck on who I should main. I only have enough to buy one of these.

I'm looking for a mid laner with a lot of poke, Safety, and a ton of early game damage, for ranked specifically. I also don't mind a higher skill cap, because I want to main a champion that actually rewards you for being experienced at them. So here are the contenders:

- So, The thing with Lissandra is, Her E's really good for escaping ganks, which is an issue I face a lot (good enemy junglers). However, whilst having good safety with her E, her combo also requires her to literally dive in with it as well (W and R depend on you diving on the enemy). Which leaves you vulnerable. Her poke is short ranged compared to other mid laners which is (eh). All in all her early damage isn't great, so I was wondering if she'd be getting a buff soon.

- Hate me for putting her here, but she's actually in a pretty good spot right now. her R is insanely broken, but I feel like nerfs are coming her way. Her mana expenditure is really off putting though, so I feel like maining ahri will just be a risk in itself considering anyone who mains a mid laner other than ahri right now is protesting for ahri nerfs.

- Okay so Ekko's a champion that im completely unfamiliar with. He's been recommended to me so many times. The thing im scared of though, is that he needs a snowball to get started, otherwise he falls off hard (which is a reason why I left diana). I could be wrong, please correct me if I am, I just don't see him being useful in team fights when he's behind, being a melee squishy diver and all.

- Same as Ekko, She's a squishy melee fighter who's unbalanced after the rework. Not sure how good she is in team fights but she falls off hard without a snowball. On the upside, she has great mobility to escape ganks which makes her really appealing to me.

- Again, I'm unfamiliar with this champion but his early damage is insane and he has his trickster ability (I think that's what it's called?)

- Syndra's probably one of the hardest on this list, (or as i;ve heard). The problem is that, after her ult nerfs I just don't feel like she's as rewarding when learned as she used to be. She has great poke, don't get me wrong, but she's really reliant on her R. Not sure how well of a champ she is right now, hope some syndra mains can help me out here.