Why are we limited to a pre-selected list? Would it be possible to choose whatever player we want from that country?

In larger countries (Brazil, England, Spain…) there are plenty of options and it would be great to have more choices that sometimes are more suitable to a particular tactic than the ones offered by the list

The list was just a simplification in terms of development effort and user effort to manage the national squad. It made it simpler for us to develop the logic to swap a player in a national squad if you could pick it from a list. What we can do is have an option to include a player in the national squad and, if you select it, present you with the list of players currently in the national squad so you could choose which one to remove.

Personally, I like that possibility!