I expected a general lack of mechanicals, but I am pretty surprised few (none?) are using anything less than a full-sized keyboard. I don't miss the numpad in SC2, and 95% of players don't use the arrow keys or Home/End cluster.
there are a couple things going on here
1st - the reason you see so many of those top players using a full-size board is because they're sponsored which directs their choice to a fullsize board because that is all their sponsor offers
2nd - the reason we don't see many compact "gaming" boards being produced is because we really don't have that many gaming peripheral companies that will actually produce a niche gaming product. Instead of producing a peripheral that might actually be superior for gaming it makes more sense for these companies to produce a peripheral that will simply sell more (just look at Logitech as an excellent example, they'll even admit to getting rid of products because they don't want to deal with smaller user niches, which is why they got rid of their MX3xx/G1/G3 line of mice)
As excellent a product as any standard tenkeyless design, or the Noppoo Choc Mini or Deck 82 might be, they simply have a smaller potential customer base than for a "normal" keyboard that customers are simply more comfortable buying because of established standards
