Accumulating too many stress tokens and still being effective needs to be penalized even more than Stress already penalizes a ship?
Yes actually. The stress mechanic is largely balanced around the concept of ships having 0, 1, or 2 stress. When at the end of turn a ship has no stress they have full access to their dial and actions, when they have 1 they entirely lose access to red moves and have to make a choice between taking actions or using the white part of their dial. When they have 2 then no reds and they are guaranteed no actions even if they use a green. Each additional stress further restricts the ships options and thus has a negative consequence.
That whole system breaks down after that though as there is little to no difference between stress 8 and stress 9. You gain no additional penalties for that 9th stress and realistically the game isn't likely to last long enough for you to clear them so there is no downside to it. That's a problem if card abilities (like Zuckuss) are costed, both in terms of points and opportunity cost, in such as way that they assume taking a stress is always a negative as it is in the 0-2 phase. No one could reasonably argue that Zuckuss would be fairly priced if he did not also have some downside, in this case stress. But that's effectively how he operates in some builds past his first use because adding a 3rd, 4th, or 100th stress makes no material difference.
