By "ARC," do you mean the rebreather circuit? "Automatic rebreather circuit?" Sorry, I'm not sure what you're meaning when you say, "ARC."
Maybe in the world of invention, the suit matters... But in the world of commercial diving (people that dive every day for a living), the suit gets very little attention. It's only function is to keep the diver warm and provide a barrier against stings and light abrasion. Other than that, there's very little attention given to the suit unless it gets in the way or creates a problem.
In the world of commercial diving (which has the same gear tendencies as recreational diving when the recreational diver dives enough), what goes on around the head is the most important part of the dive... Vision, breathing, cognitive skills, much of the diver's warmth, communication, and often times the lighting system is all handled around the head area.
Consequently, many commercial divers often have less than $500 invested in their entire rig, save for a helmet that cost them $15k... And they bought it used.
Why you'd want to invent something that solves a $500 problem (is there a problem?) is beyond me... When you could address a $15k problem.
So my good man, What piece of sci-fi dive equipment would you see come into rec diving?
Well, historically speaking, inventions have shown to trickle down into the recreational market from the military and commercial dive markets... So as I've mentioned, I believe that the next real step in recreational diving will tend towards a recreational-version of the dive helmet. It'll be small, light, unobtrusive, and house within it some lighting, full communication (that will actually work), and an mp3 player. It'll also integrate a full-faced mask that doesn't have the disadvantages of today's full-faced masks. The enire unit will be neutrally bouyant, very compact, totally unobtrusive, completely user-friendly and as easy to remove as spitting out today's second stages and removing a mask.
...But if I had to choose something other than that, it'd be the dive compressor... There is a ton of areas in that arena that can be improved opon, and there's big money in it to reward the inventor who solves today's compressor issues.
I have thousands of dollars invested in three compressors at the moment... I have one that I am rebuilding and selling to a buddy - that one's worth about $1200, in it's used-but-functioning state. Another is about two years old, and is a Bauer Oceanus - a simple "personal" style compressor aimed at the individual recreational diver. Another is a Bauer Capitano Verticus with automatic drain systems, a three-bottle cascade system, and a custom-made fill panel. I bought it for pennies on the dollar, but it cost about $28k new and today's replacement value has it sitting at something like $35k.
...All of this means that for almost any casual diver, his entire dive life rotates around "who has the compressor." It could be the local dive shop, a buddy, the local fire station, or whatever. In effect, the individual who owns the compressor is in a way like Middleastern countries - they control the supply, and that's all there is to it.
If you really want to revolutionize the scuba industry (and/or get a lot more people diving), reduce their cost/PITA factor of diving and invent an affordable, personal scuba compressor. It should run on AC110v, cost around $800, and be able to fill an AL80 from empty in eight hours, silently (or near silently) and without all of the issues of compressing air fast (heat, localized pressure issues, etc.) Filter systems and colescers should be simple, and as automated, maintenance-free and foolproof as possible.
Add a cool name, a whiz-bang appearance and some inventive design features focused solely on form over function (Bang and Olefson compressor?) and you'll have a very quick seller that will do more to revolutionize the scuba industry than any single piece of dive gear that you could possibly imagine.
Another interesting idea that you could run with is the ability to utilize GPS underwater. Yeah, I know - there's this sonar-type device that's integrated with GPS on the market today... But it's expensive and complicated to use. Find a way for today's $200 GPS units to be utilized during a dive, and you'll not only solve a problem that's been there since man first slipped beneath the waves, but you'll make a mint (and revolutionize diving, treasure-seeking, and artifact recovery) in the meantime.
...But philisophically-speaking, you're asking me, "What problem do you think will be solved in the future?" The philosophy of having a solution - and then going to look for a problem for it to solve - has never in the history of mankind been productive. That philosophy is often the basis behind much of today's dive equipment, and thus destined for failure.
Historically speaking, successful inventors have seen a problem first, then offered a new and unusual solution for it. Assuming that they protected their financial interests regarding the solution (owning a company that manufactures the solution, patents, etc.), then they can become very financially successful and be proud to be "the one that invented X."
...But the pathway to that point is clearly not marked with a solution looking for a problem... It's marked with a problem looking for a solution. That's why it's always some weird, off-the-wall, creative redneck (who's rooted in practicality and using duct tape and chicken wire in his garage) that thinks "outside the box" and makes it big in the world of invention... Rather than a well-funded University research team, a large corporation, or some big-name individual with unlimited financial backing.
...So if you want to be successful as an inventor of dive equipment, you're gonna need to do a lot of diving - not sit in Las Vegas on a computer, asking others what they think of this new idea that you have, and whether or not it'll work, and what the practical applications of it might be.
Know what I mean?
