What should I worry about for the future?
This assumes that there is something to worry about.
IMO, an EPDM roof is very durable. The material is used on countless roofs and has been for many years. The places where the roof is cut like vents, AC access, and the screws through any trim are the leak-prone points. As long as those are sealed correctly, you should have no problem. It may be that a repaired roof is installed better than at the factory. Technicians have more time and the repair company is charging top dollar for their efforts. They need to do a good job or will soon lose their customers.
The OP doesn't say if there was substantial structural damage but something like that is a whole other issue and would almost mean the trailer would have been a total loss.
My suggestion would be to look beyond the black clouds to the sun shining behind.