These are Brexiter answers (not mine) 2 OP's questions.
- What countries and products will we suddenly be able to trade that we couldn’t before?
"90% of growth in the world (in next unstated amount of time) will come from emerging markets. Those people will give us great trade deals." (too bad they are dirt poor areas of world right now and it will take many decades for those emerging markets to catch up with EU if they ever do)
- How will we be better off by losing frictionless access to the worlds largest trading bloc in return for gaining less than 1% of GDP we send to the EU?
"The EU is old & decrepit, the 90% growth countries will overtake EU" (in unstated time frame, let's just pretend UK isn't also an ageing population with same economic structural weaknesses, economic & social expectations & standards as rEU).
Even though we don’t want a border in NI and the EU don’t, we can’t avoid one under WTO rules so how is that going to be addressed?
"This is a made up issue, not real, Project Fear. Neither side will put up a border so there won't be one no matter what happens."
(or)
"The WA will become unnecessary when EU realises UK is serious about crashing out. Knowing the threat is real, the EU will cave and easily negotiate a trade deal that is great for UK UK with no need for a WA, and the trade deal will mean a free trade border in Ireland."
(or)
"The technology already exists to make the border completely frictionless. But there is a remainer conspiracy to pretend it doesn't exist. When EU realises UK is serious about No Deal, EU (& RoI) will cave and suddenly agree the technology exists after all."