First of all, they don't share the feedback before the final round.
Secondly, in the final round, I would expect a bit more structured and demanding approach to the fit part. The partners in the last round are more experienced and they will challenge every single detail of your story. So make sure that you have a couple of backup stories.
Third both in Mck and BCG I would expect some partners to give interviewee-led cases, so you need to be prepared for that approach
For all the companies "your questions to the interviewer" is an important part. Basically, it is a chance to ask questions at the end of the interview after the case. The last impression is always important. It's a free chance to demonstrate your smartness and curiosity to the partner of the company. It is also an opportunity to express your interests and mention extra-curricular activities beyond the fit interview topics.
Here are some recommendations on how to build a business sense since you got that feedback:
Building Business Sense is actually about building industry and functional knowledge.
Focus on the most common industries in the following priority (sorted by probability of getting a case): 1-retail and CPG; 2-airlines; 3-Telecom; 4-banking; 5-natural resources; 6-tech
There are several sources of info to develop business sense:
1) Cases - you simply solve 50-70 cases and get a broad knowledge of different industries, common pitfalls and questions. The key here - find good partners who already had case interviews with MBB companies
2) Company reports, equity reports, IB roadshow docs - usually have a good overview of company and industries. One of the best sources to prepare
3) HBS cases - quite useful, but not sure if lot's of them available publically. Probably worth buying
4) Books - one good book about airlines with numbers and industry analysis can give you all needed industry knowledge
5) News, Industry blogs
For each industry, you should understand:
- Revenue streams
- Cost structure
- Key performance indicators
- Key revenue drivers
- Industry trends
I strongly recommend practice drawing structures for each industry - profitability, value chain, etc
Then I will switch to getting functional knowledge and key concepts in:
- Marketing (Brand and trade marketing tools, etc)
- Supply chain (Ops metrics like cycle time and throughput time, distribution and delivery specifics, etc)
- Finance (Basic Accounting and Valuation)