They don't have anything to change to allow us to play with 5 or 6 characters especially if mercenaries are planned.
What do you mean here? I don't think mercenaries will enable party sizes of 5 or 6; they'll just replace one of your 4 party slots.
OP, I think you made a huge mistake by not including the option of:
I am fine with 4 but I don't mind including the option to go up to 6 for those people who want that option.
There's no problem here because you can select multiple options. So ^ you'd select options #1 (keep as is) and #3 (option for party size of 6).
@GM4Him - be careful about including multiple factors in your polls. Option #4 contains so many factors, each of which people can be for or against separately.