well the difference between ike and roy is that ike has may more reliable ways to set up into things, and his far greater power really emphasizes on the players ability to set up into what they are trying to get. 2.1 ike was a very easy character to use because of how easy it was to space and still get full power out of his sword. it really rewarded players for not being consistent and technical, and gave them leeway that really takes the challenge out of playing a character. i think the hilt system works, because ike still has great spacing tools despite the lesser hitboxes being out far. with the hitboxes in closer, he ca use the outer hitboxes to combo and set up for things. if this was altered, then your combo moves would be less ranged, and your kill moves would be more ranged. this would make ikes combo game relatively inefficient, and setting up into kills would more difficult, actually reducing his kill potential in some aspects, and making the close hitboxes effectively useless. with the current system, ike has more ways to manipulate all of his hitboxes, and more uses for them, giving him more tools overall. i know a lot of people are under the impression that ike was severely nerfed, and he sorta was, but i dont think that the hitbox system was a nerf. i think the things that needed to be fixed like the absurd range on his dash attack, the gigantic meteor hitbox on dtilt, and disproportionately powerful moves in relation to their range, were adressed properly. ike now has a better combo game, making him better at damage racking, giving him better potential for kills, and rewarding skilled players more than stupid broken hitboxes. his ground game, with his adjusted dash stats, now offer him more options on the ground that reward skill, and lead to more overall effectiveness than his very basic, yet obnoxious ground attacks.
i would say overall, ike is easily as effective, if not moreso than he was before. ike was considered to be so good in 2.1 because there was a lot of reward for a lack of skill. now, he is not outright as OP, but a good knowledge of the character can lead you to better more efficient results. thats my opinion anyways, im not really an ike main so i might not be fully spot on. but ive got a good amount of MU experience vs him and ive definitely noticed things he can do that he wasnt able to in 2.1.