Guild Wars 2

Simple idea, instead of making the effects of elixirs random make them conditional. Taking elixir H for an example, instead of giving either regeneration, protection of swiftness, change it so it gives swiftness at 80%, protection at 50% and regen at 25% health. This would preserve the feel of the engineer but instead of luck knowing when to use the elixir would become part of a well executed strategy.

An amazing idea right here