Hmm. I see your point.
I still prefer just using a browser on a tablet, though. I don't think the formatting is an issue - because of the bigger screen size compared to a phone I think a browser works just as well for forums on a tablet as on a PC.
Logging in... I gave up on Safari long ago because of its crapness with passwords. I switched to Atomic Web Browser, followed by iCab Mobile. Both were great for forums and anything else that needed logging in because they would actually remember passwords. I now use Chrome & love it. it'll save passwords itself, or you can sync it with desktop Chrome.
Another thing I'd recommend is 1Password. Password manager (like Lastpass I guess), and it has its own basic browser too.