I've played Awesomanuts and I think compared to DotA it's a bit more simple,yet hard to master. Different nauts have wildly different movement abilities which influence the positioning greatly and knowing which Naut moves how and how to (ab)use it is important (e.g. Froggy has the highest single jump, while Lonestar has the higest segmented jump, with different arcs and what not). It's all about timing, twitch skill and guessing your opponent's action or influencing it.

It's a neat game, but saying it's casual is like saying TF2 is a casual game (i.e. not really). The way it works also leaves a lot to be desired for. It allows premades to play against Solo Queuers which really isn't fun for either side (premades don't learn much and SQ are unorganized and easily dealt with).

NOTE: I had ~400 hrs played and I managed to reach r2 in Solo Queue (though lost it eventually).