I'm eager to get a longer zoom than my DA*60-250. I like to shoot small birds and that means fairly close distances even with a long lens and the 60-250 has what is known as focus breathing and at around 3 to 4m it's nearer 170/180mm in focal length which is not helpful. I know that the DA*300 is much better but I would like reach to at least 400mm and a zoom.
Pentax had a longer lens on their old roadmaps, but there was no indication whether it was a zoom or prime, I suspect the latter, but it may not be their current thinking. If it's a zoom and a DA*, it will probably be very pricy, so I'm considering either the Sigma 120-400 or 150-500 instead.
If Pentax actually made a non * level but WR telezoom that went to at least 400mm with a similar aperture range as the Sigmas or Canon 100-400IS L, with typically better Pentax colour/contrast, I'd be all over it in a shot, but sadly I suspect it won't happen.
My own feeling is that they may produce a WR version of the 55-300 and yet another clutch of boring primes.
If they do produce a 100-400 f4-5.6 WR SDM zoom or similar at reasonable money (no more than a Canon 100-400 L IS), then they could sell a bucketload, just as Canon do with their 100-400, but that just makes far too much sense, as would a quality WR SDM 18-200/3.5-5.6!