If they have to have 24 teams in the Euros, there is a much better way to do it. I didn't make this up myself, some mathematician did:
8 groups of three teams.
e.g.:
Andorra plays Liechtenstein
Loser of Game 1 plays Gibraltar
Winner of Game 1 plays Gibraltar
The winner of each group advances immediately to the 1/8 finals. Group winners get the advantage of playing one game less. Their opponents in the 1/8 are to be decided by an extra knock-out round, to be played between the numbers 2 and 3 of the groups (they will be reseeded).
This has multiple advantages. Most importantly it takes out the unfairness there is now, where teams can be eliminated by teams they had nothing to do with. It also ensures that during the group phase, every game the teams are playing for something, with nothing to lose. No one is eliminated in the group phase after all. It will make for more entertaining games, without reservations informing tactics as much etc. There would be 32 games rather than 36, with an extra knock-out round.
Something has to happen and I think this could be it. This Cup is the most boring one I have ever seen and this seems to be the general consensus. It may never be the Copa America in terms of excitement, part of that is the latino temperament we lack I suppose (playing with reservations never really got the same footing over there), but mostly it's just poor organization. FIFA wants to milk this with the most games possible, when really they should focus on quality. In the long run it also makes more sense commercially.
TLDR; @UEFA this format sucks please make it better