Paolo, I can well understand you don't wish to buy what you will most likely not use. Up front ASL is not cheap, though throughout its expected playing lifetime should be very good value.
I have enough counters for at least a brigade for each nationality and in some cases a division. However I have seen enough comments from posters here on GS to recognise that many, many are lucky if they have one of each core due to practical limitations of how much MMP can afford to keep in stock for sale. Not everyone has the money either.
Putting counter bulk in a BFP module would make it more difficult for the cash starved, yet I would estimate as at least no worse than buying multiple extra copies of, say, Yanks 2. Besides, BFP has this particular business model, a almost "core" approach, that has gained them great praise and success. Frankly I would think them insane to abandon a successful niche, there is plenty of competition for the 'lighter' end of ASL. Part of that success was including previously untouched vehicles and guns as in B&J, CoS and PiF. While there will be little new in OS, maybe you might consider what would be unnecessary duplication as a price for BFP's otherwise excellent ASL lines. Just like life, nothing goes perfectly. Personally I think it would be a pity if you missed out on what I would expect to be an excellent product.
PS: I was and am not a great enthusiast of giving the Poles their own colour scheme, but was part of an overall excellent package, so ...