My guess is the league wants to get the possibility of trades/trade rumors out of the way before All-star weekend so that attention can be focused solely on All-star weekend.
I can't stand all-star games in any sport, so if this means there will be fewer trades I don't like it, but if just expedites things 1 week earlier, then I actually think it might be an improvement because it gives coaches the entire All-star break to plan (an maybe even practice a little) for the integration of newly acquired players.