What I do in my online Wilderlands game is use negative hp, you die at hp = negative max. This makes death rare (rarer than 3 death save fails = dead) but also makes popping dying PCs back up again during the fight is unlikely. After an hour if a PC makes a death save they can short rest, spend hd and potentially wake up & be active again.
Not using revivify seems fine, it's never been used IMC. I would probably rather keep revivify and lose raise dead/resurrection/true res though, I think that would keep the fear of death more strongly while reducing in-game lethality. There was no raising IMC until late in the heroic tier, and only
a couple NPCs (cute, female companion NPCs) have ever been raised, never any of the dead PCs.
The 5e game would work fine with no raising (including revifify) at all - rare, permanent
death works well.
Start at level 5 - I do that, new PCs start at the bottom of the Tier or with half the XP of the dead PC, whichever is better. Sometimes I have different starter points, eg in my 5e Varisia game
the current start level is 4th. 5 works well for PCs in the 5-8 range, for level 8-10 PCs I start them at 8th. Currently in my Wilderlands game the active PCs are 12-14 and start level is 11.
Eventually I'll raise the start level to 14, then 17.
Read more: http://www.enworld.org/forum/showthread.php?482389-Finding-5th-edition-too-quot-safe-quot/page13#ixzz44kPPLmP0