Travelled to the nether from a newly-made overland portal to a very old (pre 1.4) pre-existing netherside portal. Horrendous lag, which has been reported before, and also as the brown earth 'world loading' screen appears I can hear a ghast shooting at me. I have no means to dodge, because I can't even move until the world has loaded. The second the world does load, the ghast fireball hits. This is rather unfair. Then the entire world crashes anyway. Crash dump attached.
I assume being defenceless against attack is just a side effect of the terrible lag, but the combination of unfair attack plus lag may be what's causing the crash.
By the way: on the wiki, one had multiple bug severities - crash, major and minor - aren't you going to add those to the tracker?? Also, why don't you add custom closed statuses, such as Closed - Treat as Feature Request and Closed - Treat as Annoyance, rather than just marking those things as invalid. That would make it easier to find the feature requests and annoyances again in the future, rather than just lumping them in with all the genuinely invalid bug reports closed as such.