You've headed multiple projects in which you've overseen the addition of new abilities, classes or cool mechanic that will become features of existing games. What are some of the most important lessons you've learned along the way, both in terms of design and implementation? Magdalena

Here are just a few: Players will never sacrifice performance (especially damage) for utility.

Players won't choose X over Y for thematic reasons. They'll choose Y if it's more powerful and be salty that they can't play X.

Ranged units are powerful. Ranged units that are fast moving (the cav archer problem) are nigh unbeatable.

Players hate mechanics that feel too random. They will push to remove randomness.

The coolest ability in the world will be dead if the art and sound are uninspiring.

Something that is really, really hard to execute still isn't fair if other players feel like they can't compete with it.

Diminishing returns is a thing. It's better to get something to 90% quality and move on to a new ability than spend an additional month getting to 95%.

Affordance is a thing. Abilities should make sense and be comprehensible.

It is very easy to srumble on something really novel and then ruin it by sticking it on every character.

The most satisfying characters have unique inputs (in essence a mini game they have to play that other players don't interact with) and unique outputs (something they being that does affect the game for both allies and enemies).

The best abilities are mechanically interesting, thematically resonant, and satisfying to execute. It's easy to give up and settle at two out of three. (But see dimishining returns.)

Hacking something cool in that causes bugs and makes programmers mad is the wrong call, even if it's really, really cool.

Players don't like it if you take something away in order to give them something else. This tends to lead to bloat over time, which also isn't awesome, as you just layer more and more mechanics on top of each other.

Simple changes with profound results (say an AoE civilization that starts with extra villagers) tend to be the best because they are simple to understand and hard to master. However, it's also a newbie designer trap to sacrifice everything in the name of elegance. Some designs work very well despite their jankiness.

If all else fails, targeted stuns are always fun... for the stunner.