I think the focus on debt is misleading - most businesses carry debt. In itself, debt is not a bad thing. You’d need to compare Walsall’s debt ratios to other established League 1 clubs.
I also think its misleading to say the club has no assets when the last set of audited accounts show it has around £7 million of Current/Non-Current Assets.
In terms of valuating it by earnings, its one of a number of methods. It shouldn’t be discounted totally but it is flawed - for example if someone is slamming in big accruals (say for example, to pay back a big loan maybe?) it would throw it out. I’d probably be looking closer at the cash flow than the profit.
Personally I wouldn’t put together a bid price for the club without a bit more information.