Is there any way to make slurp work over multiple parenthesis/brackets? So that slurping at [[[1| 2]] 3] (with the cursor at |) would result to first [[[1| 2] 3]] and then [[[1| 2 3]]]. Alternatively, is there any command that moves elements into other forms, so in this case moving the 3 inside the inner vector, not as the first element of the outer vector?

i use paredit so to move the the 3 inside the brackets to its left i would put my cursor on the right bracket and then ,> to move that bracket to the right (to bring in the next token)

Well, yeah. If moving, then vim-sexp could also again move the parenthesis, or I could delete the elements