... there are many big issues which can only be tackled in an efficient manner in the multilateral context through the WTO.
Trade Facilitation was negotiated successfully in the WTO because it makes no economic sense to cut red tape or simplify trade procedures at the border for one or two countries — if do it for one country, in practical terms you do it for everyone.
And this is not the only issue that’s inherently multilateral.
Financial or telecoms regulations can’t be efficiently liberalized for just one trade partner — so it is best to negotiate services trade-offs globally in the WTO.
Nor can farming or fisheries subsides be tackled in bilateral deals.
Disciplines on trade remedies, such as the application of anti-dumping or countervailing duties, cannot significantly go beyond WTO rules.
The simple fact is that very few of the big challenges facing world trade today can be solved outside the global system. They are global problems demanding global solutions.
Maybe that's part of the reason why governments push bilateral and regional agreements? To avoid the big challenges?