I think it's a 'simple' problem of multiplicity. So many different devices and operating systems (Windows in various incarnations, Apple OS's, Android, Linux and probably others) it's perhaps not surprising that it's a challenge to get a site to work on all of them.
However I no longer use my phone to access the site at all (due to the problems Coinery mentioned) and it's slightly annoying to miss out on some of the features ... including some of the administrative powers I used to have on the old site.
I don't know if it's poor programming or just the best compromise that can be reached, given the difficulty. But I suspect it can only get worse with time ... and if it does I shall probably just give up. Hopefully that's an incentive for the designers to get a grip on things, though I'm not holding my breath on that.