I think you must only be listening to the most recent lessons. If you go back in the archives you will find different people doing them.
Some Korean have very crisp clear voices but a great number, perhaps more than half, of them sort of use a mumbling lazy speech pattern. It is like the difference between an English speaker who clearly enunciates "I .. am .. going .. to .. the .. store" and one who says "I-min-na go-dada store" In any case, if you really want to understand spoken Korean it is very important to listen to such "stoned" native speakers. And yes, a lot of Seoul girls talk like their nose is plugged up. Not all Koreans sound alike. As you probably know, there are several "dialects" of Korean, for instance in 경상남도 (the southern province where Busan is located) the dialect has a distinct whinyness in addition to other unique features. And the 조선말 spoken in North Korean is also very different sounding than standard (Seoul dialect) Korean.
Regarding the responsiveness problem. The site is basically unmanned - if you get an answer on these forums it is more often a volunteer than an official representative of the site. Also, the lesson quality and quantity has gone down quite a bit from the former days, but I think the problem there is that there are so few serious students of Korean using the site, and even fewer paying customers, that the proprietors simply cannot afford to pay for quality help.
The first seasons of the Advanced lessons were fantastic, absolutely first rate, but then they switched to the audio blog format and things went downhill from there. The most recent bloggers haven't even reviewed the previous seasons lessons so often they cover the same subject again --and yet are doing a worse job at it. So yeah, I agree -- the site has become "lame" (as in crippled); therefore any benefit you take from it depends on YOU.
열공 (열심히 공부) 합시다