It really depends on what you want to do with the next champion you get. Do you want to be an assassin that tries to go in and clean up after your team, or do you want to be a tank/split pusher champion or counterjungler? I can't really say much because it would be to biased from me since Shyvana is my favorite champion in league but I'll try to not make it so biased even though I personally hate Katarina lol...
Is currently in an "ok" spot right now (I think?) and her pre6 game isn't to amazing but it's honestly safe since you can just sit back and farm or harass with your Q, and you have a dash that can teleport you on to anything that has a health bar, on a pretty low cool down (when it's maxed). Her ultimate is very strong and she lowers down 15 seconds on all her skills on all kills/assists, making her a very snowballing champion (which snowballing seems to be the meta right now). The only lane she can really do though is Mid, though she can do alright top lane depending on the matchup. She is very strong but requires the person playing her to have very fast reflexes and knowledge of when to go in and target priority. Though if she jumps in to early or the enemy team was smarter, she will get hit with 1 CC and that will basically make her almost useless since her Ult is the bulk of her damage.
Is a Top lane or Jungle (Both she can do very well...though top isn't as popular anymore. But I still do it lol). Personally she is in a pretty good spot for both top and jungle, she does very well with either Devour or Cinderhulk (devour is better on her though) and with the new Rageblade, she is a monster once she gets going. Top lane she can fight most other melee champions, I think the only top lane champion that gives me problem right now is
. She can be built as a full tank, or a fighter...usually I'd just get
and go tank the rest of the way. When played as a jungler, her ganks aren't very good and easy to get away unless you went
for shyvana jungle. She's better as a Counterjungler, and for counterganking since she can actually 1v1 most junglers and has very fast and safe clear times.
I'm just going to stop there, I could say more about each champion like possible builds, runes, masteries etc but going to wait until you decide which champion.