Sort top level accounts as Assets, Liabilities, Equity, Income, Expense, No-Top-Level.
Traditional accounting sorts accounts in the order shown in my subject line. The Capital accounts, Assets, Liabilities and Equity sort at the top, in that order, and the income and expense accounts follow. This division supports the idea that income and expense close into capital at the end of the fiscal year.
I go nuts looking for Liabilities since it's at the bottom.
This sort order should appear in the accounts tab, the parent account field in the new account/edit account dialog, the transfer-account dropdown in the register, in import allocation, and anywhere else that the chart of accounts appears.
Anybody who has done accounting anywhere else will be more familiar with that sort order than alphabetical.
Within the top levels, alphabetical should be OK.
If it's thought that this will inconvenience existing users, perhaps an option could change the top level sort order.