MECE is necessary, but it is not what makes a structure strong. A structure is useful when the buckets are tied to the client's objective and help you decide what to analyze first.

Instead of starting with standard labels, ask what would have to be true for the client to succeed or fail. Then build the structure around those drivers. The same case can require very different buckets depending on the objective.

A good test is whether you could copy the structure into another unrelated case without changing much. If yes, it is probably still too generic. If useful, this guide on case structure vs. case framework gives more detail.

MECE alone gets you a structure thats technically correct but generic because it's built around case-wide categories instead of the actual question you are trying to solve. This is fine most of the time on the first level but you need to make it specific starting the second layer.

A few things that can help:

1. Anchor the top level to a specific decision, not the high level topic (investment, cost cutting etc.): If the question is "should we enter this market", the structure shouldn't be "market, competition, financials". Instead they should be 2-3 things that actually determine whether the entry makes sense for the company/situation. 

2. Push your hypothesis down to the 2 or 3rd level. If you struggle with structuring without your "generic" guardrails, then start with the first more generic level. But the second (latest 3rd) level of your structure should be stating what's actually going on, not just another neutral category. That's usually where people stop to early and leave things generic. the top level looks fine but the bottom never reaches true "problem solving quality".

3. Use the prompt you received to derive hypotheses. If the case mentions declining margins alongside a recent expansion, your cost bucket shouldn't be generic "fixed vs. variable". It should already be hunting for whether the expansion is the driver of declining margins. Generic structures wait for data, while tailored ones are shaped by data.

 Bottom line the best way to create a great structure is to actually ask yourself questions/build hypothesis to get to the driving factors of the problem first (why are costs increasing, what are driving factors, where could opportunities lay etc.) and then structure and check if it's MECE.

hope this helps, 

Alexa