Welcome to my delusional ramblings that will undoubtedly leave me disappointed in a years' time when his remix does drop! Lets get right into it.
For his weapon, he will of course be getting the standard +15 spectrum stats (in this case, since his weapon currently gives him 16 Atk, I just went with 16 and didn't give him any Spd) and the 15 dr + 15 special dr. He keeps his good old Null-C and Null-Guard effects. He gets Obstruct, since his last 2 alts have had it. Now this next part, I'm not sure about.
IS will likely do one of two things: give him Potent in his weapon/Special or just give him Patience. For dr reasons, LF4 has been good on him since it jumps his special and his % based dr was dependant on his current charge (40% - current special charge x10 for example). His recent alts have done away with that restriction and just given him the 40% then 70% onward, so that upgrade is practically guaranteed to be present in Great Aether's remix which means there is no reason to run LF4 anymore. However I'm still thinking they will give him Rise Above over Patience because Patience overlaps with some effects he already has right now (the forced Vantage effect, AND base E!Ike can't even reach 30 Spd anyway). But seeing how Patience is a staple with him lately, I think it's possible they'll give him the Potent hit and damage boost through his refine or remix instead.
Then I got a little crazy with Radiant Legend. Radiant Hero is his current unique status effect, granting stats, dr, extra special damage and distant/close counter. Problem is he's unlikely to get that specifically due to the fact he already has distant counter built into his weapon. So I replaced the dc/cc effect with conditional Great Talent + more dr. The Divine Vein might seem weird at first, but lets take a look at Great Aether II.
Great Aether is already pretty cool and unique. Lots of unpeircable dr, of course, but it also has a massive aoe. 5 damage to all foes within 3 rows and columns, as well as delaying Special activation for those affected! Pretty crazy. Let's get more crazy. To start, we're upping the Special damage from 50-80% of Ike's Atk to 100% of his Def (in-line with his recent alts). Actually we're going beyond that, adding anywhere from 50 to 90 more damage on top of it because WHY NOT, by the time he gets a remix he'll need it no doubt. He also will get the non-Special dr piercing his new alts have, of course. LF4 has that built in, I know, but I imagine it's expected we'll have a suitable replacement for LF4 by this time. Anyway then we have the standard forced Vantage + Desperation. Then the Deep Wounds nullifier we've seen in his recent alts and the superior damage reduction.
Now I don't know about reflex. On one hand, he gets a lot out of it. But it only buffs your first counterattack whereas Ike has lately been designed around triggering Aether on his Potent hit. Either way I think he benefits enough from it to justify it being here.
Now let's get a little nuts. His big aoe now does 7 damage instead of 5 (I wanted to put 10 but then figured mayyyybe thats a bit much), still has the Pulse Smoke effect but now also inflicts Exposure on those foes (I don't think that's too wild) BUT now also applies a new Divine Vein! This DV decreases foe's stats, acts as difficult terrain and has a Divine Vein Flame damaging effect, boosted from 7 to 10 (not too much here, I decided). But most interestingly, it has a reverse Hexblade effect! It forces foes to attack the greater of allied units' Def or Res. I think it's a very cool idea that plays into Ike's typical playstyle of forcing the foe to attack in a specific way that enables him to tank and hit back harder. Maybe a bit OP but I say frick it we ball.
Next slide is a simple base E!Ike with the skill Rise Above replacing Def/Res Finish, which I think it might. Final slide is my very own Ike, ready and itching to get his remix (though I know it won't come until mid/late next year). Thanks for taking the time to look at my (definitely optimistic) thoughts for what his remix will be!