1) The fact that the Hylian shield is made up of metal would seriously diminish the impact that it absorbs. A hit from a strong weapon like, say, a two hander would transfer all the force without issues into Link's arm, maybe even breaking it if the blow is strong enough. And because of this, any hit into Link's shield would most likely make him lose balance or simply lose his shield (as in dropping it into the ground) because of the impact of the blow.
This reason right here is why all shields were made out of wood in the olden times. Metals suck when it comes to being good shields.
But I am aware that Link has a wooden shield, but then Ike also has a tomahawk. These weapons could easily chop and break shields when they impacted them when thrown.
So: Link uses Metal shield? Ike gets close and any hit, shielded or not, counts. He either shields, feels the full impact of the force, gets his arm injured and falls down which equals death in these scenarios. If he doesn't, then he is chopped.
And if he uses a wooden shield, then Ike throws a tomahawk, breaks his shield making it useless and then just goes for the kill.
Add this to an incredible close combat skills that surprass that of Link's and you got yourself an insta win here.
2)
http://en.wikipedia.org/wiki/Armour
Ctrl-F arrows. Plate mail I.E high quality armour could deflect arrows with little issues unless said arrows were fired incredibly close to the armoured person because of the materials, how slippery metal was and the curved angle armour has.
I'll say it right now, Ike does not have a complete armour set, so his protection is limited. But he does have something that could double for a nice replacement if used well.
He has some a complete set in his left arm. He will use it to protect his lower torso when he is approaching Link, and while his legs and head are uncovered, it is indeed very hard to target those body areas in the real life. This is the reason why sharpshooters always go for the torso: trying to hit the head or the legs is pretty **** hard, especialy if the person is moving.
Also, Ike won't need to approach that much actualy.
He only needs to be 75 feet or less from Link to reach him technicaly.
http://www.youtube.com/watch?v=njG1STYKMF8&feature=related
Look at this video. It only took one second for an axe to reach a target 75 feet away from him, and it dealt nice damage to a sturdy target like the piece of wood.
So Ike just needs to get just within 75 feet to throw an axe to Link, forcing him to block. Dodging with such a fast projectile coming towards you is almost impossible unless you do a mad flip that throws you into the ground. Then Ike uses this chance to do a mad dash towards Link while he is recovering from the blow and get close enough for Link to consider ditching the Long bow for the sword.
Ike could also throw even more axes while approaching. Ike isn't limited by one in his games. He could bring three.