The Capcom Unity website has created a thread that the developers will supposedly be looking in on for suggestions/feedback. As both a competitive player and someone who understands the need for mass appeal, I took the time to make a list of my own that I think will help make the game both a commercial and tournament worthy success. Feel free to register and add your own suggestions, but for the love of god, try to base them on them educated ideas.

Making SFIV a mainstream success

Characters

-With a subtitle like "A New Beginning", most of the characters should be new. Ryu and Ken are already in it obviously, and I know a lot of people want to see Chun-Li, Guy or Guile in it, but other than that, I'd recommend you use mostly new characters. Look back on what designs people liked and which they didn't (SF3's character designs bombed for the most part) and draw them based on that feedback. The public generally seems to prefer semi-modern looking "people" rather than freaks and weirdos.

-Concentrate on creating a balanced roster of unique characters rather than jamming as many in as possible. I'd rather see 12-16 well made characters than 35 poorly balanced ones.

-If you're going to have a joke/comical character, don't make them suck. You should want to laugh at the character, not the person playing them.

-Be very careful when creating "user friendly" characters. Chun-li in 3rd Strike is a good example of how an easy to use character can end up being too strong, and negatively effect both the way the game looks and plays at tournaments.

-Understand that making a character big and slow is a big disadvantage and they need something to help make up for their large hitbox and lack of mobility. All too often, grapplers and other large characters are low-bottom tier.

-Make sure you carefully weigh a character's strengths in relation to the others. Looking at someone like Twelve and then Ken in 3rd Strike is confusing on a balance level.

(I know I'm being repetitive in this section, but poor balance will kill a fighter's longevity if it's the same 2-4 characters all the time).

Online

-If you're planning to go online with the title, consider releasing balance patches, but be careful of what you remove. Sometimes glitches or unintended move properties add to a game rather than detract from it. This also allows you to sidestep the negative stigma that comes from releasing multiple pay-for revisions of a game.

-Make sure the netcode is solid. In fighting games, a single millisecond of lag can often mean the difference between a win or a loss. Gamers should be able to play one another cross country without significant delay. All the ladder rankings and match-making systems in the world are useless if it doesn't run smoothly.

-Make sure it's easy to get in to both public and private games, and allow options for re-matches and character switching between matches. It's amazing how many fighters don't even include these basic features.

-An option to toggle voice chat during matches would be nice. Good natured trash talking is part of the fun of fighters. This also allows players to form a dialogue with one another and give each other tips on how to improve if they're so inclined. Avoid minor stumbles like forcing the player to set both P1 and P2 controls in order to play online. Things like this can be very confusing to new players if it isn't explicitly documented somewhere in the game.

-If there's an overpowered boss character of some sort, for god's sake, don't allow them online.

Stages

-If there is an arcade release, include a stage select in the VS mode. Nothing is more irritating than seeing the same stages/hearing the same songs over and over again if only a few characters are chosen competitively.

-Interactive environments can have a huge effect on the game's balance. Tekken 4 was so badly broken by wall combos and uneven surfaces that Namco abandoned the latter completely for the next game. If you're going to have stage interactivity, make it integral to the way the game plays rather than throwing it in as an afterthought because that will likely break the game. The safer approach is just to have the interactivity on a purely cosmetic level.

Gameplay

-It should play like its own game rather than like the Alpha series or the SF3 series. Think carefully about how things like alpha counters, custom combos and parries changed the game system positively and negatively and plan accordingly.

-Concentrate on making it a good VS fighter first and worry about including extras and single player incentives after. Extras and un-lockables should complement a solid fighting engine, not the other way around. Don't fall in to the MK: Armageddon trap.

-Play test the game thoroughly. Fighters can easily end up being broken if they're not examined in-depth before release. Look for things like infinites, abusable loops, kara-cancelling type glitches, etc.

New Players

-One of the biggest issues with modern fighters is that they make no real effort to ease new players in. Some sort of tutorial/lesson mode would be greatly helpful to people trying to learn the game. Obviously, you can't account for high level stuff that hasn't been discovered yet, but just teaching people the fundamentals can go a long way. Emphasize tactics as well as execution/combos.

Graphics/Art Direction

-Don't be afraid to go 3D if you haven't already, but keep in mind that the game still needs to feel "right" control-wise. The fastest way to tell whether a SF game's controls feel wrong is if the jumps are too high and floaty (ie. The SFEX series) and the movement is too stiff. This is still Street Fighter not Virtua Fighter or Tekken and it should move at a different pace.

Marketing

-Hype the game up online. Release little tidbits of information regularly to keep the game fresh in people's minds. Too often, companies will go months or even a year without saying anything and people will start to forget about the game or even doubt that it's going to be released in good form. Games like Smash Bros. Brawl have kept people interested through small, regular releases of new characters and content.

The people Capcom should be listening closest to are those people who know how to play these games at higher levels, but understand that Capcom needs to appeal to a mass market and that this could potentially open up new doors for the fighting game genre in the mainstream. What we need are more progressive suggestions that look past trying to include old game play mechanics or niche techniques.