permadeath: yeah this can work, in quite a few situations really, hardcore modes can be really exciting, and TBOI taught me that if the game isn't actually that long, permadeath is the best option. however it can quickly become frustrating if the game is several hours long, is a ***** to play and then you die, and takes you ages to get back to where you were.
Always on PvP: again, can work pretty well. personally if the option is there i always play on a PvP server. gankers annoy the hell out of me and i usually don't do it myself, but world PvP can be hugely fun, especially when it becomes huge crowds of people just fighting to the death. in these cases a LONGER respawn time should be in place, as being able to instantly revive takes the joy out of getting a kill in my eyes.
permadeath with always on PvP: well i hope they designed the starting zones well, because about 90% of players won't leave the fucking place. i get pissed off if i lose 2 hours worth of time in gaming, about 15 minutes of work and i'll be fuming, but putting tens to hundreds of hours into a character (several of my WoW characters are over 20 days of game time) and it being lost forever... fuck that shit