To stop abuse, representatives had called for a fair use policy to stop travellers from buying cheap SIM deals in one European country and then abusing those benefits in another. The new plans are a first look at how the Commission intends to deal with that issue. They appear to lean on existing free movement agreements made by Member States that require some citizens to register their residency if they stay for a period of more than 90 days in a year. It's determining whether a person can a considered a traveller or a (semi-permenant) resident -- the latter of which would possibly need to buy a local mobile SIM.
Since April 2016, operators have capped roaming charges at €0.05 per minute, €0.06 per SMS and €0.20 per MB. The new plans will lower call and text message prices to €0.04 per minute and €0.01 per SMS, while data usage is being cut to 0.85 cents (€0.0085) per MB. To help people who regularly travel between countries for work, the Commission says that as long as they log onto their home network once a day, they will not be included in the 30-day and 90-day limits.
This is not to say that carriers cannot be more lenient with their roaming restrictions. These limits are effectively a basic right for all Europeans, and you can expect to see operators continue to differentiate themselves by offering better deals.
Representatives will now invite member countries and the EU's telecoms regulator to comment on proposals before they're adopted on December 15th. Overall, it looks like consumers who enjoy "unlimited" data plans at home will be offered the same opportunities abroad, as long as they don't exceed average their carrier's domestic usage limits.