It's true fish is generally more verbose, as it has less magical syntax. fish is also missing some niceties like `set -e` and `set -x` which we would like to add, but the main focus is interactive use.

Happily the begin/ends in ifs are no longer necessary:

   if not command test -f $dest
      or command test $src -nt $dest
     # stuff
   end

In this particular case, you can simplify it further with test's operators:

    if command [ ! -f $dest -o $src -nt $dest ]
       #stuff
    end

which is comparable in length to bash, though other cases will certainly be longer.

I'm a very happy fish user but this is one of my pain points as well. If you want to define a function, the syntax is light-years ahead of bash, including named arguments (and closures!), but it took a fair bit of googling and eyebrow-wrinkling before I could figure out the way just to set a default argument for that function.

What I ended up with was (for a shortcut for generating a password on the command line):

    function pw --argument length
        test -z $length; and set length 16
        python3.6 -c "import secrets; print(secrets.token_urlsafe($length))"
    end

When I last needed something similar, I wrote it like

    not command test -f $dest
    if or command test $src -nt $dest
        # do something
    end

It saves on the begin ... end, but is confusing to look at. Nested conditions are really not very ergonomic in fish.

Yeah, wow... I would have to spend at least 15 minutes figuring out what that does.

use ; in place of &&

I think you should actually use "; and" in place of &&. That said I still wish fish support && and ||, if only for the times when I copy and paste some one-liner off of stack overflow and have to rewrite it.