I think you're discounting the versatility of bair (despite the nerfs), and uair, which are both safe and cover good distance. While you can't use them in neutral often, utilt and ftilt fulfill their roles faithfully. Dtilt, while shorter, is essential for mixups due to its low profiling nature as an alternative to his aerials, to help punish opponents who jump preemptively or try to land. While jab is no longer good, it at least fulfills the basic role of a generic jab for an up close option to continue or relieve pressure (boring I know).
I think the big stinker here is fair since it has above average landing lag, AND below average power, for its frame data and reach. I think all that Ike needs to get fixed is some combination of range, damage, and landing lag buffs on his fair. It doesn't have to be as strong as his smash 4 counterpart, but 12 damage, 12 landing lag, and a tiny bit more range will help even out Ike's kit. I don't think that's really asking for all that much. Everything else is a pipe dream, so I don't expect changes like a larger bair hitbox below no matter how badly I want it, or at least lower FAF.
Also, nair is being overrated, yeah. As good as nair is, it doesn't fulfilll the basic role most other nairs attempt to accomplish by breaking strings. That's why it's so strong a tool. It does low damage so it needs to combo well.
Overall, I disagree with the weak neutral (disjointed aerials that demand respect that are difficult to punish, multiple tools that can be used to mix up, etc), lack of approach options (discounting bair, as well as the versatility of uair and dtilt, with multiple situational options to stuff aerial and grounded approaches in utilt and ftilt). Neutral might be weak for a high tier, but I think it's easily above average overall.
Ike does lack responses to pressure by design. The best he has is, if you predict an opponent will continue to push buttons, you may use grounded aether to utilize its 5 frame super armor. As well as bair if you're lucky though that's rare. Overall lacking a bit compared to the free frame 3 nairs that many other characters have. Other than that, he has to use global options to finesse around opponent's options before he can hard punish them. Fortunately, the global options in this game are much stronger where Ike can utilize them with his decent air speed.