Istanbul has an oddly good system, where vans run a set route, but you can ask for them to stop wherever. I feel like this would be a better balance that would allow for greater coverage, while also lowering the cost of equipment and in the very least, eliminating the need to walk as much to a stop. It's also faster because it's basically a large taxi, so once the van is full, you only stop where the passengers need. This is only a supplement there, but I think it would work better than the majority of bus set-ups currently used.