Forcing a standard charger for all is a good start, but smartphone manufacturers should also be forced to make batteries switchable again. For smartphones and tablets batteries are usually the first parts that degrade and "force" people to buy a new device. Manufactures say that with switchable batteries their devices would no longer be water resistant, but that looks like a lame excuse. If a device is water resistant despite having an open USB or lightning port, that proves that should also work for the contacts that connect the batteries.
A normal smartphone battery is built for about 500 charging cycles. After that the capacity is down to about 80% and from there is even goes down faster. So after two or three year you either need a new battery or a new phone. The manufacturers love that. They even profit from making it hard to switch batteries. I hope the EU will stop that practice. Not just for smartphone, but for all devices with rechargable batteries. Electrical toothbrushes for example. That would help the environment much more than a universal charger.