I agree that a standard 6 month waiting period is unnecessary and may be harmful. They are reacting, I think, to the divorce problem that is so prevelant amongst self-professed Catholics. Now, not one of the traditional Catholics I know have been divorced since becoming traditional Catholics. Some may, perhaps, have divorced before finding tradition, but I don't really know about that either.
I can understand not allowing a couple to get married unless both parties have been traditional Catholics for a lengthy period of time in order to prevent pretended conversions in order to get married. But two traditional Catholics who desire marriage should be able to get married within a fairly short period as long as they discuss the proposed marriage with the priest in a detailed fashion. It seems to me that since the Banns of Marriage are to be announced for three consecutive Sundays (Canon 1024), and the pastor must ensure a proper education prior to that, the minimum time would be about two months, give or take a few weeks.
However, I can hear the hoots and hollers now here on CathInfo if a traditional Catholic priest allowed marriages after only a short period of time and the couple later divorces and blames the priest for not giving sufficient marriage preparation.
For the clergy, it's damned if they do; damned if they don't.