How wrong is this

[Jim greengo]

That is what this does. The drain still goes through the floor so I call it an S trap but I suppose you could just as well call it a P trap.

Not if you install a San tee in there and a waste arm coming off of it.
Then come off of top of San tee with a fitting to roll back towards back corner of cabinet then another fitting to straighten it back out,extend above last offset as high as you can and install the trailer vent.
It's no longer an s trap.

 

[checkthisout]

Yeah it could be better.

Everything wrong under there with both the plumbing and wiring could be fixed in less time than it took to post that pic and make the thread here.