It’s Hardcore. There is no “pvp” even when someone is flagged. Noone will flag for a fair fight. Vanished rogues on classic are dead after one arcane explosion. The only chance a low level has is complete immunity and a speed potion.
Agree there will be few if any fair fights, I expect most fights unfortunately would put you at a significant disadvantage both where the aggressor would have the initiative as well as being above your level.
I just don’t think immunity for 8-12 seconds and a speed pot will get you away from anyone that really wants to kill you especially since I suspect you’re most likely to be facing a hunter or rogue where the speed wont help, and once the immunity is up, your dead if they catch up to you, also if there are people in the area, it will be easy for them to stalk you and wait to attack you when your already in a position of weakness.
For me rogue simply has more options, and if you want immunity, you could always use a LIP. I would also probably avoid the common combat spec and go with a spec more in subtlety though where you can move faster in stealth. Hunters will be problematic though with mark. Obviously in the end though it will come down to the person, and also if they want to run or fight. From my own experience leveling a paladin on a PvP server, escape never worked, though a lot of thats probably on me, and I never had a ton of consumes to fall back on.