I have a strong feeling that the Riot are doing everything to slow down the progress of EU, at least by the example of other regions.
For example, getting into Challengers for a new ultra-mega team is difficult. You have to go through the open quals for the regional leagues, win the season, perform well in the playoffs, and then do the same thing in the promotion tournament.
In practice it turns out that all regions have a chance to go through the open quals, while in EU it's more and more like a franchise league. By doing so we will hardly see an influx of new teams, the divide between the T1 scene and T2 already seems huge. I see the only solution to how this could all be done better.
Make one big regional league, for participation of let's say 16 teams. Increase the number of teams in Challengers to 16 too. At the end of the season, the 8 best teams in the Regional League play against the 8 worst teams from Challengers in Promotion tournament. The 8 worst teams in the Regional League will drop out and start next season with a closed qualification.
In the end, everyone will benefit. The level of regional leagues will increase, as well as the quality of broadcasting and the number of spectators. There will be a chance for new teams to prove themselves, the matches will be more tense, because no one is immune from a relegation to a lower division, etc.