Yes, I've been through Malta on quite a few trips. I'm well familiar with those roundabouts - even in rush hour. And while there is congestion queueing, it's nothing out of the ordinary and nothing that didn't exist before the roundabouts were installed. You can't design these intersections to be free-flowing in all conditions, but the fact is, roundabouts are safer than traditional traffic signals in almost all applications, they are free-flowing in almost all instances, and they have lower long-term operating costs. Without providing specifics as to your original point, we then have to rely on the general consensus, backed by research and data, that these roundabouts are better in instances where it is properly applied. And there is nothing out of the ordinary about these roundabouts to signify that they were improper.
And what are you talking about with this "50k" number? AADT is only around 14,000-16,000 on SR 67. US 9 is around 11,000 to 15,000. Even rush hour statistics, pulled from NYSDOT, aren't out of the ordinary.