While the Deltawing is an interesting design idea...simply put it can't compete genuinely at LMP1 levels. If reliability was solved maybe it would match up better with the older slower LMP2 cars, but it really just drives around being noncompetitive. They get excited when it sets a decent lap in qualifying.
You want to do something weird? Build the Deltawing as the new LMP3 car. Two birds with one stone...save some gas, weight, blah blah blah. I love weird stuff in motorsports, but it serves less purpose with no cars to compete against. Much like the Mazda diesel prototype from the past few years.