I do understand your opinion. And yes the winter transfer window can be seen as some kind of competition falsification. Take for instance STVV last year, great before the winter break and then De Norre and Bezus were sold because they did want to transfer. This probably did cost them a place in POI.
And yes we in Belgium are a lead-up competition. But this of course also makes our competition richer. Lots of promising players are willing to play for a Belgian team, take Nygren for instance, a few years ago he never would have come to Belgium. This is because the quality of our little competition isn't that bad and they know that lot's of top teams are scouting in our league!