The sport needs a name rebranding first of all. For Americans, the name is great, if not brilliant. They can love the patriotism, feeling part of something and now that they truly invented the game. They can also celebrate being home of the World Champions every year. The sport will never become global because it only wants to be national. It is truly America's game and I truly believe a European team would fail to succeed.
On the other hand, you could argue it is called the NFL. The EPL has succeeded in football (soccer) as has Spain's La Liga. Surely the relocation of a team to Europe would not mean that much more travelling for teams who already travel on long haul flights every week of the season. The rumour is though that the team would not have a specific base and be travelling from city to city around Europe week in week out so how would they create a passionate and enthusiastic fan base? Supporters are used to going to home games more than once or twice a year.
There will be no home grown stars to cheer on. The best we could hope for is David Beckham or Jonny Wilkinson taking over the kicking/punting duties for a team. As much as you could see many Rugby players having the transferable skills, which team is realistically going to take someone on who has never played the game from a different sport compared with Americans brought up on the sport and who play in many professional set ups at college.
Surely, the sport needs to start at grass roots and build itself up if the NFL realistically wants to take off in Europe. Paying a load of Americans to tour around and play at various stadiums/arenas around Europe is not going to ensure a long and successful life for NFL in Europe. The sport needs to be encouraged in schools, colleges, universities. I cannot see this happening with the dominant sports already being played around Europe.
Long may the Wembley games happen and maybe increase these to 3-4 a year around various places in Europe but a team will never truly find a home in Europe.