Stil think the dumbest move they've done with the series was depart from having a regular Arcade mode on SC3 and on, those were simple but always fun. What killed SC4 for me was how much they focused other modes including character creation on stats, the story mode was closer to an arcade mode but was still poorly done.
If anything that's what Tekken still gets it right, they try new formats but they usually keep the arcade mode. And Ghost mode feels more rewarding than anything SC has tried in a similar vein.
Oh definitely, although SC3 still had a normal arcade mode (they just called it quick match or something for some illogical reason). However it was just a bland arcade mode with no fluff (no ending movie or dialogue during the rival battle, just a ending cutscene of Abyss exploding) or score/time challenge for replay value like in most arcade modes, just like Tekken 6 and Tekken Revolution's (still will never understand why Harada didn't tie prologues and endings to arcade in T6, but instead made that stupid 4 match mini arcade arena mode to get them).
But anyway, yeah I too hated how they got rid of all the traditional modes. No time attack, no survival (well SCIV still had it as part of the tower), no team battle, no form of mission mode, and botched arcade modes in IV, V, and Boken Destiny. Quick Battle, or whatever it's called, that's in Broken Destiny and V, tried to be a take on Tekken's Ghost Battle, but just ended up frustrating and unfun.
Hopefully SC2HDO is the start of them going back to the arcade roots, with normal modes plus a fun mission type mode you got in 1 and 2.
On a random note I really hate character creation in fighters, glad MK dropped in after 1 game and no others have really tried it except Soul. I like customization, and maybe dressing my favorite character up like another one of my favorite characters, but character creation in fighters just never clicked with me. If you go full blown customization it ends up broken like MK Armageddon or just a for fun thing like Combot in TTT2 (which is banned from ranked and stuff). However to make it balanced you have to do it like Soul where it just a reskin of a existing character, but that's just boring to me. Playing as what's basically a generic emotionless robot you created with random sets of generic voice options, that uses the style of a character with a actual personality, is just dull. It's not like a RPG in which you create a character that is supposed to be a in game portrayel of you where you choose what it says and does, it's just some character model in clothes, if you create a character from another game or show it won't have that characters personality, and it won't have the unique mannerisms of the characters its a skin of.
Maybe that's just me though, when I play a fighting game I want to use a character that has there own personality and mannerisms, so I would rather developers spend time on developing the actual cast instead of neglecting them to make a bunch of face options, body options, generic voices, and such for El Generico. Lucky for me it seems most developers agree.