One of the things that annoyed me was that I had to choose my 30 man pre-Euros squad, then a week later cut it down to 23. In between these two events was...nothing!
The ability to play a friendly or two during this time to help me choose between fringe players would've been nice, or at least a suggestion from my ass man about who trained well or even who should've been cut.
I can see that international training alongside club training could be a bit complicated, but they could at least allow you to train set pieces, match prep, post-match conditioning and team bonding during tournaments. Although this way I guess at least all teams would be equally disadvantaged and rubbish at penalties seeing as nobody can practice them!