One cannot regionalise the worst accent - there are shining examples of it from all regions in the majority of people. Indistinct and grammatically incorrect speech are both extremely common. The majority of people do not seem to be interested in speaking properly, as long as they are understood by their audience is all that seems to matter. In fact, it is "uncool" in many circles to speak properly - inverted snobbery at its best.
Two examples of "accent evolution" are Des Lynam the sports commentator and Brian O'Connell from RTE news - both fluent speakers of plain English. These are two Irishmen but they got up, got out and got away which is a pre-requisite for most Irish people to cultivate their accent. Speaking of hick accents, why do members of the Gardai interviewed on RTE seem to look and sound like total bog hoppers? They are a parody of a PC Plod type of policeman / woman and do nothing to dispel the stereotype of the paddy.