Divinity Original Sin has done a great job at making group tactics fun and interesting by allowing abilities to interact with the environment as was as other abilities. Everything from electrocuting an enemy standing in a puddle of water created by another characters rain spell, to teleporting a creature that a team mate summoned such that it self destructs into a group of enemies, or even turning an enemy into a chicken so that it will wander away aimlessly which will provoke an attack of opportunity from another character. What makes it fun is that the combinations are free form, and make your group feel like a clever, dynamic, and coordinated team rather than a bunch of role based individuals. An improvement I'd love to see is an ability crafting feature so the player can come up with abilities and combinations themselves rather than buying pre-set abilities. Crafting could be done by allowing certain ability parameters to be selected such as having an ability be a projectile, target the ground, or a specific creature type or body part.