I disagree with SFIV having difficult combo’s at all, they are just annoying because your not allowed to fuck up. Hell if it comes down to the wire I’ll drop a combo intentionally and block sometimes just to HOPE they are mashing reversal.
Risky =/= hard. Most people can hit their combo’s 99% of the time with very little training mode compared to rom or Iron man infinite.
Good for you that you and your friends have some sort of natural born talent specifically for links but that’s really not the case for most of us.
Tekken is easy, But it varies depending on the character, Jack-6’s BnB is fucking easy with some practice on his kick after the bound, D/f+2, 2, F,f+1, F,f,f+4 b+3, 2,2 or you have Kazuya’s 1 frames combo’s. d/f+2, Perfect EWGF, EWGF, EWGF, DEWGF you can probably get another EWGF on the DEWGF
http://www.youtube.com/watch?v=rIWdMKSGFAA 0:34-0:40 kazuya combo
Ino from Guilty Gear gets pretty crazy. Sadly their are characters that do most of what she does for less execution 
Tiers for Fighting Game Execution
S a.k.a you must be a combo machine to compete
A - need some skills or gtfo but anyone can learn 90% of the shit
3. Guilty Gear while their are some DUMB hard combo’s in this game most of them aren’t truly needed to be scary like in Fate/Marvel
4. Melty Blood - Mostly easy combo’s but some characters like Satsuki and Kohaku can be really intensive to the point their BNB’s are all character specific with different timings and … AHHHHHHHHHH
A-
5. CvS2 - Roll cancels and PTF will keep you in training mode awhile.
B
Everything else
C
Marvel vs Capcom 3 - you know why
for me:
COTA: manual superjumps after launch 
XvSF: im just no good at 3p 3k marvel
MvC2: im not good at 4 button marvel either
sf4: the inputs are so easy i mess them up, like racing someone who is so slow you lose
Devil May Cry 3
Kof 96 by a mile none of the games mentioned so far even comes close
Definitely F/UC
Some HnK shit can be pretty damn difficult, like general Kenshiro bnb is not hard, but, the more advanced Raoh/Rei/Toki combos are not easy. TBH I couldn’t even do Toki’s bnb D:
Post an example. I refuse to believe it is more difficult than fate “by a mile”
Have you played 96? i’ve played fate unlimited codes i never really played it to heavy but i never really had any execution problems with it my main problem was actually remembering the combos not really executing tking is nothing obviously there’s gonna be hard combos but i felt in 96 even executing something as simple jumi in hp hp fireball was tricky, the timing was ultra strict the inputs had to be EXACT, it pretty notorious for having the most retarded input readings ever.
You had to do everything ultrafast ultra accurate when you start coming into super not to mention multihit glitch hitting into your combos it gets ridiculous.
I forgot about HnK that was pretty tricky, but again it’s more a length of combo thing for me
Super Turbo Super combos (hardest shit ever, even top players rarely do Ryu / Ken’s st Fierce, Super)
Alpha 2 Custom Combos
MvC2 high level crazinessss
Tekken 3 throw chains (does this count? King or Bruce are crazy hard)
The rom infinite is easy as shit to do and easy to set up. The Iron man infinite has a hard setup. Fucking up a Rom can benefit you by giving an unexpected reset.
Too nice.
It’s more learning to convert random air-air and stuff like that to rom that I think is hard. I know a lot of people that can ROM but I see even pretty good players drop it sometimes when it counts so it’s not exactly hard to fuck up though getting random crossup reset is sexy.
Also I’d put HnK in A tier it’s about has hard as those games imo but it’s no FUC. Like anyone can do a combo but generic air combo and real unscales with stance cancel loops and shit like that is the difference between night and day. Only game where if I get 1-shot I don’t get angry because you deserved that kill. Also a lot of TK’s can’t just be randomly TK’d there’s a timing to it so that you don’t jump but slow enough the move actually reaches jump cancellable frames … AHHHHHH … bad memories.
I believe KoF2002 deserves some mention. Some BC mode combos are incredibly hard, in my opinion. QCF DP QCF DP QCF DP QCB HCF, all with super tight timing windows.
Are you not confusing with A2 VCs? The A2 ones are basically cr.RH, repeat a move such as short tatsu or lightning legs, then do some higher damage special at the end, like a RH tatsu or Frc SRK. It is too easy, in fact.
But the risk comes from the fact that the combo system has such strict timing windows for links. The system is designed around an annoying arbitrary brick wall (1 frame links) then it’s combined with the games defensive nature (and easy reversals) that you’re punished for even the slightest error.
And eff that, IM infinite is easier than pulling of some of the links in SFIV consistently.
Chun Li, cr. mk, mash legs, mash :d:,:u: while mashing legs so get her tenshokyaku. Heck you can even catch them on the way down by mashing legs for extra damage.
I’ve only had experience with mvc2, tekken, and sf so:
mvc2 still blows my mind to this day. Fly/unfly shennagins and crazy shit with magneto, it’s tough but amazing to watch.
KOF 95 took some pretty damn good execution for the high level combos and even when they simplified the combo system for later games like 98, you still needed to be precise in your inputs. I first played KOF 95 in 1996 and my first month was spent messing up high level Takuma and Kyo combos because I was used to the simple as fuck chain system in Alpha 1 or two in ones in SF2.
People seem to keep forgetting SFIV has no 1-frame links. Plinking increases any link by 1-frame in theory. Only one’s I feel are hard are one’s with REALLY long delays between inputs like ryu cr. FP after f+FP or fei chicken wing link but to say they are on the same level as something as F/UC or what not … nooooo.
SFIV is just badly designed lol. It’s the main game I play so whatever.
A2 CC’s are dumb but not hard … I still have nightmares of A2 chun fuckkkk her level 1 custom that can be mashed into half my life. Don’t forget it can be started off an unblockable low via “Valle CC” …
But aren’t her hit confirm very versatile, a lot of her hit confirm comes from ambiguous mix ups/cross ups.
There were some fairly complicated specials and super moves to pull of in Capcom Vs. SNK 2…, and the game deserves special note because it’s not like Tekken where all of the moves in the game are long strings of “button algorithms”. Instead it’s a straight forward high strategy and timing execution based fighting game like your standard Street Fighter title- just with some characters having a handful of crazy long moves (which really need to be practiced and memorized) mixed in.
I haven’t played the game in a while, but off the top of my head- I remember Geese, Rock, and Hibiki having these types of long and fairly difficult to execute moves.
Not to mention the game was loaded with different ‘groove’ options which regulated how you accrued supers, whether or not you could roll, soften throws, tech…, and a bunch of other things I’m forgetting.