Count me among the PPO breakfast crowd that is bummer. Of course I wasn't "guaranteed" a relatively empty Main Street, but that was 100% the reason we made the reservation. I'm willing to pay $25pp for breakfast at BoG if it also gets us 15 minutes to mosey up Main Street, take some pictures, and enjoy a calm start to the day. But if all we're actually getting is breakfast, I'll save my $100 from BoG breakfast and just grab a coffee and some pastries at Main Street bakery instead.
We were going to also eat breakfast at BoG, so I'm not sure why some posters think just because you want Main Street time doesn't mean you aren't also going to eat breakfast. People like all sorts of different aspects of the WDW experience - just because something is important to someone it doesn't mean it has to be important to everyone, and it's completely legitimate to be disappointed if something you had been looking forward to is no longer a possibility.
All that said, in general, this seems like a good change, as now lots more people get some ambiance time on Main Street before starting the day without scrambling for the limited PPO reservations. I do agree with a PP though, that it's SO frustrating that Disney has set up a system where the guests have to be reserving things 180/60 days in advance to get some of the most coveted attractions or reservations, and they go and change plans with very limited notice. We're now within 30 days of our MK day with the BoG PPO, and I had planned FP+s assuming we'd be in fantasyland PPO. Now I'm going to have to rearrange things to accommodate the changes, which is very frustrating.