At the moment the only Very Light Jets (VLJ) really come from Raytheon with their Premier 1. Cessna are next up with the Mustang, and there are a number of smaller comapnies such as Eclipse making their own versions.

I think Embraer have once again seen the way the market is likely to develop in the next 10 years with more people wanting small, fast, and economical private jets, largely for business use (efficiency and productivity) with a few more of the social elites being able to pick them up for only a few million as well.

The development costs will undoubtadley be higher than the Legacy which as you say was just an ERJ135 spin off, but I think this decision will pay off for Embraer within the next 10 years.