Personally I would love to have tp cmds. Except only trusted+ would get this because they already proven themselves to mods/ops that they won't grief. (similar to builders on classic and smp is easier to get lost in imo))
Also trusted should only have /tpa <username>, /tpaaccept, and /tpadeny because obviously it'd get abusive if they could just tp without the other player having the ability to say no. Also trusted+ wouldn't be able to deny OPs/Mods tp requests (then again couldnt OPs/Mods just use /tp without the 'a'?)
I say that /tpa should be used at your own risk because if you decide to use it and you get griefed its your own fault. If the person you teleported was someone you wanted to have there anyways, what would stop you from taking however many minutes/hrs from finding them and bring them there anyways? /tpa's just convient and quicker especially when you have joint projects with other members that requires resources from various locations or when you want to trade somewhere private (how many times have someone walked in the middle of someone trading in the market and stole goods?).
The /back cmd is OK but for some reason doesn't feel good enough to be a /tpa subsitiute because you'd have to already have visited that location and then warped somewhere else and ONLY warp once otherwise you'd overwrite the location.
I know Relkeb and Opticalza have already discussed this and feel it just wouldn't work on this server but I gotta try right
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Side Note: Also for some reason when I've died and typed /back after spawning I NEVER return to the site of where I've died but rather to the place I warped from BEFORE I died which is pointless, or a bug?)