Anivia is a fun champ to play and she's pretty chill(pun not intended). She isn't the hardest mechanical champion to play but she is very rewarding once you know how to manage her mana early game and the damage you put out. The fact that she is slow shouldn't steer you away from playing Anivia. What she lacks in movement speed, she makes up in being able to control how fights work out. For example: using your wall to catch someone or the whole enemy team in the jungle and then stunning them while your whole team obliterates them. Anivia is overall very fun to play because she can carry the game or she can become a second support by just looking for stuns and walls. Anivia takes quite a few games to learn and a lot more to master. Her auto-attack will throw people off since it is really slow. Her main combos are relatively simple to learn. However, wall and ult placement is where mastering her becomes a little harder. Learning when to place your wall is essential because mistiming or placing it just a few pixels ahead or behind something can result in your teammates dying. For ult placement, be very careful because although it is on a short cooldown, in a team fight, if the ult placement is messed up, it can cost your team the fight. Anivia's ult provides a slow and more damage on your E. You want to make sure the enemy team is spending as much time inside your ult since it provides damage over time. All this just comes with practice!!