A real problem beats a clever app concept
The first question is not whether the idea sounds exciting. It is whether the problem is painful enough that people will change behaviour, pay attention, or spend money to solve it. Good co-founder opportunities are grounded in daily operational friction, compliance pressure, wasted labour, lost revenue, or a workflow people already hate.
If the idea only becomes interesting after a long explanation, it is usually too weak. The best opportunities tend to sound obvious once you hear them from someone who lives the problem every day.