While i agree with the idea of a IMOQ remake, i actually disagree with most of the ideas you're giving.
GU's graphics? I'd say no, for the mere reason that GU's graphics are actually "outdated" to this point. Yes, a remake must obviously game improved graphics, but they don't have to copy another graphic's games to achieve that. With the current technology, i'm more than sure that a IMOQ remake can easily be made with graphics far better than GU's...the simple idea of seeing Skeith with graphics at the level of God of War 3 or FF13 is orgasmic enough. So yeah, improve the graphics of course, as that's sometimes the most important thing to do in a remake...but, don't copy GU's, keep the IMOQ style and simply use technology to make it far better-looking.
Different gameplay/GU's gameplay? HELL NO. IMOQ was the series it was also because of it's MMO-like gameplay, and though it was freaking easy overall, i really enjoyed it...not for the gameplay itself, but for the feeling it gave to you. If you're gonna change the gameplay and make it GU-like you might as well make a new SIGN series and make it Naruto/Bleach-action-paced >_> The aspects of gameplay, particularly the way you fight monsters, the way the areas are set up, the micromanaging between your party members, and the way skills and attacks are used MUST stay....else you're just making a whole new game with the characters and story of an existing game. No one except a few crazy fans would want Kite doing Skill Triggers and Rengekis and Awakenings and all while being surrounded by a cylinder DX
I'll admit though, IMOQ can get quite boring and repetitive at points, and although i personally didn't mind that (since indeed...MMO's consist of doing the very same actions a million of times, and it's only fun because you do it with others), several people do complain about it...so alright, improve the attacks and add flashy skills. Make it so that Kite does different combo attacks, like X-X-X-X is one combo, X-X-Pause-X is another, X-X-Hold X another, etc. Give a wider range of skills, and make some skills able to be used together with the skills of other characters...or even combo skills, like if Kite and Balmung are together and close enough, you can choose as either Kite or Balmung to do an unique skill and they'll do it together...you could even have the camera focus on them as they jump and do stuff...would be similar to Rengekis but different and more fitting for IMOQ, and will make battles far more entertaining and less tedious since you could be much more creative with them. And though i don't like this idea...you could even have some "preset actions" for your party members...so that if they are against some sort of elemental enemy, they'll automaticly use an elemental skill they have, or automaticly heal themselves, or use certain items depending on their conditions. I don't like that because it makes it too "automatic"...But oh well, in the end it would be optional, and it would be great for all those people who hate having to micromanage and set up every action to do with everyone, making it easier and less frustrating for long chain of battles.
As of the difficult of enemies and all...well, i could throw out a whole ramble in here saying that i want a Skeith of pretty much the difficult of FF9 Ozma, and a Cubia last battle/Corbenik a bit harder than those Satan and Demi-Fiend thingies from SMT...but that's just me and my sado-masochist gaming mind of wanting a REAL BADASS challenge this time XD (I mean...you're against "monsters" that aren't supposed to exist in the game and go far beyond the boundaries!! You just can't HOPE to defeat them no matter your level and attacks, even with that spiffy book and that pretty bracelet!! D8) So...all i could really ask for is for a smart enough AI, both for the enemies and your team, and be nice enough and say to decrease the Infection level rate, or even add items that decrease it...if anything, to make the last dungeons more of a challenge of skill than a challenge of luck.
So, those are my ideas for a remake...and if they were like that, or close enough, i'd be very excited and content about it, and would view it as both a great and fitting remake of the series, as well as a darn good game on it's own :P As of the console this would be for...i actually think it would be best for a PS4, or for the next, non-portable Sony console. I think it's too early for making it on the PS3, and i don't see this all happening on a portable console.