To step in, I want to say I find this conversation interesting. It makes me wonder if it is the developer's call to dictate the inputs to his/her game or if the gamer deserves the say?
I recall a dual-stick style 2D shmup, with 360 degree exploration and attacking of enemies, with a non-dual-stick input and I argued to the developer that his sales were hurting with this design as I did not like the inputs. He modified the game to include dual-stick input and I loved the game much more, however his sales were already dictated by his launch.
Back to my question, I believe I have the say on my inputs, however I also believe if a gamer wishes to remap the buttons on a controller then they should be allowed. I think it comes down to if the game is changed or not. If you wish shoot was "B" instead of "A", then this does not change the game. However, if I put non-dual-stick controls into Score Rush, then I feel (I may be wrong) that this is not the game I intended to create. Rather, it is not the experience I intended to create and share.
Now, all of that said, if it was demonstrated to me that someone could use non-dual-stick controls to dominate Score Rush, then my argument against it would become weak as the experience I really want to share is shmup domination. The reason Score Rush has multidirectional controls in the first place was for domination. To kick ass. (And, also out of necessity due to the full widescreen nature of this vertical scrolling "bullet hell".)
Another part of this discussion I could jump into is the arena vs. scrolling shmup idea. Score Rush is not an arena, it is a vertical scroller, and also the enemies all come from the top. So this appears to indicate that not much directionality is required, as opposed to arena shmups. I would say this is true for the most part, but in certain expert play examples there is the need to fire quickly in multiple directions. The points in the game come from killing the enemies as fast as possible, and to do this you wish to be as close as possible. Sometimes you are so close you are to the left or right of a boss, and then a popcorn enemy comes to your right or left. Just an example. Other examples are staying very close to the top of the screen during non-boss sections, which requires lots of left and right shooting. Watch some top replays for examples:
http://shmups.system11.org/viewtopic.php?t=34509.
EDIT: The top Score Rush (X360) run:
https://youtu.be/D7SOsLgBreI
So, I could argue that Score Rush needs arena style firing to be the best. I am sure someone could play with the arcade style controls and prove to play effectively (maybe not the best). In the end, it is something I could code in (not in this version which is close to release), but it is also something I would be unable to beta test and perfect as I have with the dual stick controls. This, more than anything, is a reason why I likely would not code it in. I am the lead beta tester of my games, really, and it's hard to put anything in the game that I do not use. It would suck if I coded in a mechanic for experts in these forums only to do a poor job of it.
I appreciate all of your input, as always! I love that you even care about my games at all!