The "make it work work perfectly from just statistics" can come later, when time is more flexible. Probably on an identical non-production copy of the environment, if that shows the same performance characteristics. ;)
The planner/optimizer is good at its job. In general, better than I am. If I can inform it about a particular shape of data, all queries around that data will improve. If I tell it exactly how to execute one query, only that query improves.
Additionally, setting statistics to 10000 is really easy. Easier than tweaking a query. Creating custom statistics is more work and may or may not be worth exploring as a quick fix. But if you know the data is shaped irregularly, why wouldn't you make sure the planner knows about it?