I see you're awaiting a post as to why ike is a good character, so I'll do my best.
Typically, when a character is too poor for competitive play, it's not a lack of strengths, but excessive weaknesses. Let's attack those first.
Ike has slow attacks: this is true, easily the slowest in the game. While they do take a long time in general, many of them have extended hitboxes that stay out a long time as well. These moves include upsmash, uptilt, upair, his A combo, nair, and fair, which are arguably his best attacks anyway. While it may seem limiting to use only some attacks in a game that has less than 20 attacks already, it is actually in Ike's benefit to use them as they stay out for a long time. The above listed attacks are also difficult to punish when combined with the other property of the attacks- the range. Smash has historically been a game in which range is superior to speed. For example, in Melee, marth won the majority of professionally hosted tournaments, despite that Fox, Falco, Sheik, and Falcon are faster than him. While many aspects of smash have chanced since the previous game, this is actually the opposite. Brawl rewards range even more than speed simply because there is a void of technical skill to overcome it. Ike has a combination of range, priority, and power that lasts on extended hitboxes, and the game simply lacks a means to remove that advantage from him. In effect, against most characters, even fast ones that are already acknowledged to be top tier material such as Metaknight, Ike can actually attack their attacks and pull an easy victory. Nintendo, when it took out most of the smash technical game, actually rewarded power characters over speed characters rather than the other way around.
Ike gets gimped: well, this one is debatable for a few reasons. Primarily, Ike is nearly impossible to edgehog. During ike's up B, he throws an invincible hitbox up to clear off the edge for him before following it, both of which together last longer than the edge invincibility required to perform the edgehog. While side B can be edgehogged, ike has 2 things going for him to avoid that: 1 DI is more pronounced in brawl, and the ike player can simply choose to DI towards the stage and up B in many instances instead, and 2 side B actually requires much less charge time than it looks, and I often personally use it to go over my opponent on the edge to land without any lag. Even so, if Ike has any recovery weakness, side B is it. The same could be said about standard edgeguarding, which is nearly impossible for any character as it is. Heavy characters in brawl do face a problem in that faster characters can simply do a combo move into a kill move, or proceed to combo a character past any hope of recovery off of the stage. Examples include Metaknight's upair to up B kill combo, or pit's arrow edgeguarding. While these may seem hopeless or Ike, a simple answer has not been experimented with enough, and that answer is just airdodge. Ike can DI towards his opponent and mash R/L to escape a surprising amount of combos that would otherwise KO him. Even so, after Ike air dodges a single attack, he will have enough time to up B to either the ground or to an edge, which is why DIing at the stage is so important. Air dodge to up B with DI towards the stage will usually allow Ike to live until a throw kills him, so it becomes character dependant. Against some characters, Ike will still be KOd by a backthrow under 140, scenerio dependant, but vs other characters without them, such as again Metaknight, Ike can easily live past 250%, which is probably much longer than Nintendo had initially expected.
Ike gets spammed: well, here I have no argument save to block them. No characters can really projectile abuse Ike indefinitely besides Pit, but Pit can also do this to much faster characters anyway. Lucas is another pain to deal with. In my opinion, the characters that spam Ike are probably his only counters.
Now, I'll focus on Ike's more hidden better qualities.
Ike can gimp: man, can he ever. Despite the immense difficulty of edgeguarding in brawl, Ike is probably one of the best at it. A few tools include the downtilt spike which usually kills at 0%, the downair spike, which usually kills after 20%, up B gimps from the edge, in which ike spikes the opponent on the way down and grabs the edge. If the opponent comes from anywhere other than within a 45 degree angle from the edge, Ike can fair them. When above the edge, if the fair is air dodged, ike can simply attack again. If below the edge, it's ok, because Ike can SH fair off, and if the opponent air dodges, Ike can procceed to 2nd jump bair as they come out of it before using up B and easily making it to the edge. The bair will usually stage spike, but if the opponent techs, they still get hit by up B as it goes up.
Ike kills at relatively low %: even if your opponent outplays you, it's ok, as you can still generally do half as well against most characters and still go about even with them. If the Ike player is as skilled as you, well, good luck.
Ike's pressure game: while Ike may have difficulty approaching the opponent, once the first hit is in, Ike can do a lot of things that require your opponent to screw up. They usually will though, for various reasons unless the opponent is familiar with your style. A good example is jab grab. Normally, jab would never combo to grab for Ike, but your opponent may hold shield just to avoid getting hit by the full combo. Another example is forward throw to regrab, since again the opponent is likely to hold the shield to avoid ragnell. Ike gets a lot of grabs this way. Ike can also do things like jab, turn around SH low bair, back into the jab combo to weaken the shield, simply because the game lacks the technical aspects to punish it. In general, the more creative Ike is during the actual fight, the more likely he is to land hits that really shouldn't hit. This is another flip side to previous games, where playing safe is generally the best way to play.
That about summarizes why Ike should be just fine for competitive play in my opinion. His weaknesses can be overcome for the most part, and his strengths can be magnified a great deal.
edit: for the record, I think all of ike's special moves aside up B are more or less useless and rely on your opponent to be stupid when they have no incentive to do so, unlike the previously mentioned tricks where at least blocking ike is reasonable. Same for his downsmash.
