IAE engines are used on MD-90 and some A320 family planes.
A wing is an intergrated part of a plane and you cannot just shrink or extend its span without a lot of consequenses on the design of the rest of the plane. Tail, controls etc.
With unchanged sweep back angle the balance will change if you don't move the wing root forward. If you do that the space for the landing gear goes to pieces, and the structures, which connect the landing gear and the heavy wing, must be totally redesigned.
Increased wing span means a lot heavier wing structure.
A 30 feet extended wing span means an entirely new plane. An MD-11 optimized for a 200 feet wing would be the nearest thing you could come to a three engined 747-400, and it would share very few design features with the original MD-11.
Best regards, Preben Norholm
Always keep your number of landings equal to your number of take-offs