The official Team Fortress 2 Blog has details from Valve's Robin Walker on the next class pack for Team Fortress 2, which will concentrate on upgrading the Heavy character. Word is they are taking a slightly different approach to this update, as they are opening the process a bit to offer players insight into their goal, which is summed up like this: "Make the Heavy more viable when he has no Medic to pair with." They describe the constraints they face in this task, while outlining the skills a good Heavy should display. Here's a bit on the considerations they are facing:

Constraints:

    > It shouldn't have a cumulative effect when being healed by a Medic as well. Heavy/Medic pairs do pretty well as it is.

    > It shouldn't significantly change the Heavy's role, relative to other classes. In particular, it shouldn't significantly encroach on another class's role.

    > It should be understandable for both the user and the player it's being used on.


Extra:

    > How much work is it? How many new models, sounds, effects, etc?

    > Does it deepen the Heavy's skill curve? Is it easy to learn? Hard to master?

    > Is it an interesting tool to choose relative to the base Heavy weapon it's replacing? What scenarios can you envision in which each is useful? What arguments can you raise for why each is better than the other?

    > How often does the Heavy need to think about it? Is it something he uses once every 5 minutes, or is it something he needs to be constantly thinking about? A greater impact on player decision making is generally a good thing.

    > How many other features of the game does it affect? Often, the best ideas are "economical", with a small set of required actions, but a wide set of resulting effects